p53-Dependent and -independent transactivation by the E6 protein of human papillomavirus type 16

The mechanism by which the E6 protein of human papillomavirus type 16 (HPV-16) transactivates heterologous virus promoters has not been established. In this study, the involvement of p53-mediated transcriptional repression in transactivation by the HPV-16 E6 protein was examined using several virus promoters. HPV-16 E6 transactivated the TATA box-containing simian virus 40 early promoter and the Rous sarcoma virus long terminal repeat in p53-containing cells but not in p53-deficient cells. In contrast, the adenovirus E2 promoter was transactivated both in p53-containing and p53-deficient cells. These results indicate that the transactivation activity of the HPV-16 E6 protein is mediated by p53-dependent and promoter-specific p53-independent pathways.

Cloning and characterization of two transcripts generated from the mel-13 gene positioned adjacent to the mammalian Polycomb group-related gene mel-18

We previously isolated the mel-18 gene, a mammalian Polycomb group (PcG)-related gene with homology to bmi-1 oncogene. We show in this paper the existence of a new gene, mel-13, which overlapped with the mel-18 anti-oncogene. We discuss the relationships between mel-13 and the mel-18, bup, and Su(z)2 genes.

Expression of variant CD44-messenger RNA in colorectal adenocarcinomas and adenomatous polyps in humans

BACKGROUND & AIMS

Recent studies have shown that some variant forms of CD44, a transmembrane glycoprotein expressed on various cell surfaces, might be involved in tumor progression or tumor metastasis. The aim of this study was to analyze the expression of CD44-messenger RNA (mRNA) in colorectal cancer and colorectal adenoma to further elucidate the role of CD44 in colorectal tumorigenesis.

METHODS

The expression of CD44-mRNA was examined in 90 specimens from 44 patients with colorectal cancer or colorectal adenomatous polyps and in the peripheral blood leukocytes from 7 healthy volunteers by reverse transcription-polymerase chain reaction and Southern blot hybridization.

RESULTS

Strong expression of the epithelial form and variant forms containing exons 11 or 12 of the CD44 gene, which conferred metastatic behavior to rat cells, was detected in primary and metastatic tumor tissues, whereas it was very weak or not detectable in normal colonic mucosae, normal liver tissue, or peripheral blood leukocytes. However, adenomatous colorectal polyps also showed as strong an expression of epithelial and variant forms of CD44 as primary and metastatic tumor tissues.

CONCLUSIONS

These results suggest that variant forms of CD44-mRNA might be expressed in an early stage of colorectal carcinogenesis.

Production of monoclonal antibodies against quail Pax-1

Monoclonal antibodies (MAbs) against quail Pax-1 were generated using a fusion protein of the C-terminal part of Pax-1 and glutathione S-transferase. The MAbs generated could detect quail Pax-1 protein by Western blotting and immunoprecipitate it from whole cell extracts of quail embryos, indicating their usefulness for biochemical analyses of Pax-1 protein function in development or oncogenesis.

A feasibility study on L-[1-carbon-11]tyrosine and L-[methyl-carbon-11]methionine to assess liver protein synthesis by PET

We studied the potential of L-[1-11C]tyrosine ([1-11C]Tyr) and L-[methyl-11C]methionine ([Me-11C]Met) as tracers for measuring protein synthesis rate (PSR) in the liver by PET and proposed their metabolic models.

METHODS

In the liver and plasma of control and cycloheximide-treated mice injected with [1-14C]Tyr and [Me-3H]Met, incorporation of the radioactivity into the acid-soluble fraction and chloroform/methanol-extract (CM), RNA and protein fractions were measured. Data were compared with those from rat studies with 11C-labeled analogs and PET.

RESULTS

In mice, liver uptake of [Me-3H]Met was over twice as large as that of [1-14C]Tyr. Similar uptake patterns of the 11C-labeled analogs were found in rats by PET. In the mouse liver at 1 to 6 hr after injection, approximately 69%-73% of the 14C was detected in the protein fraction, whereas approximately 65%-70% of the 3H was in the CM fraction, which reflected phospholipid synthesis. In plasma, the percentages of the protein fractions were approximately 73%-76% for 14C and approximately 36%-46% for 3H. Gel-filtration analysis suggested that 80% of the 14C-labeled plasma proteins was albumin originating from the liver, which corresponds to approximately 25% of the total labeled proteins synthesized in the liver at 6 hr. When protein synthesis was inhibited by cycloheximide, the liver uptake of the [1-14C]Tyr and the protein-incorporation of 14C in the liver and in plasma were decreased dose-dependently. On the other hand, uptake of [Me-3H]Met was significantly enhanced in the liver due to increased incorporation into the CM fraction.

CONCLUSION

[1-Carbon-11]Tyr can be used for measuring the PSR in the liver by PET. Liver uptake of [Me-11C]Met mainly reflects phospholipid synthesis through the transmethylation process.

Systematic mapping of autonomously replicating sequences on chromosome V of Saccharomyces cerevisiae using a novel strategy

We have developed a new procedure for easy and rapid identification of autonomously replicating sequences (ARSs) and have applied it to the analysis of chromosome V of Saccharomyces cerevisiae. The procedure makes use of the ordered lambda phage clone bank of this chromosome that we have constructed, and includes transposition of a mini-transposon and selection of transposon-containing derivatives, isolation of their DNA and circularization at their cos-ends, transformation of yeast cells with the circularized DNA, and scoring transformation frequency. The transposon used was derived from Tn5supF, contained the yeast LEU2 gene, and was placed, together with the hyperactive transposase gene, on a mini-F plasmid for stable maintenance in Escherichia coli K-12. Sixteen regions of chromosome V showing ARS activity were identified, of which 12 were newly found in this work. Thus, the procedure will be useful for systematic genomic scale analysis of ARSs in yeast and related organisms in which ordered clone banks have been established. The average distance between adjacent ARS-containing regions was approximately 40 kb. Two-dimensional gel electrophoretic analysis of chromosome replication indicated that one of the newly identified ARSs was functional as an actual in situ replication origin, at least under the conditions employed.

Anatomic study of the bronchial arteries with special reference to their preservation during the radical dissection of the upper mediastinum lymph nodes

BACKGROUND

The anatomy of the bronchial arteries was studied, with special reference to their preservation during the radical dissection of the upper mediastinum lymph nodes.

METHODS

The bronchial arteries of 71 cadavers were studied macroscopically by use of the surgical field of right thoracotomy. The small branches difficult to identify macroscopically were described by x-ray imaging with digital subtraction angiography. Their anatomic relationship to the adjacent organs was observed microscopically.

RESULTS

The bronchial arteries arising from the intercostal arteries (the intercostobronchial arteries) were observed in 66 of 71 cases. By use of the surgical field of right thoracotomy the intercostobronchial arteries were easily found and preserved. All cadavers also had other bronchial arteries arising from the aorta. These were difficult to preserve because of the depth of the surgical field and the location of their course in the dissected area. Bronchial arteries had established connection with each other via the vascular network in the tracheal proper sheath. India ink injected into the intercostobronchial arteries was observed in the tracheal proper sheath and the submucosa of the trachea.

CONCLUSIONS

Saving the blood supply to the trachea is possible with careful preservation of the intercostobronchial arteries and the tracheal proper sheath during radical dissection of the upper mediastinum.

Structure-activity relationship within a series of degradation products of tautomycin

Tautomycin, a protein serine/threonine phosphatase inhibitor, was chemically degraded, and five derivatives were investigated for their biological activities. None of them exerted any inhibitory effects on the activity of protein phosphatase types 1 and 2A. However, one derivative, named TM2a, induced a significant morphological change (bleb-formation) of human myeloid leukemia K562 cells. TM2b, the trimethyl ester of TM2, did not induce bleb-formation. Thus, the maleic anhydride structure played an important role in the biological activity. The biological properties of TM2a toward K562 cells resembled those of a phorbol ester, rather than of tautomycin. The phorbol ester-induced bleb formation was abrogated by a non-specific inhibitor of protein kinases, staurosporine, and by an inhibitor of protein kinase C (PKC), H-7, but TM2a-induced bleb formation was abrogated only by staurosporine. Enhanced phosphorylation of the two proteins was observed after their exposure to TM2a. This suggest that the effect was not due to any inhibition of protein phosphatase 1 or 2A, but rather to the activation of an unidentified kinase, possibly of the PKC family, or to inhibition of a protein phosphatase other than type 1 or 2A.

Computer survey for likely genes in the one megabase contiguous genomic sequence data of Synechocystis sp. strain PCC6803

Using the computer program GeneMark, the open reading frames (ORFs) previously assigned within the one megabase sequence data of the genome of the cyanobacterium, Synechocystis sp. strain PCC6803 (Kaneko et al., DNA Res. 2: 153-166, 1995), were re-examined. Matrices required by GeneMark for its statistical calculation were generated and modified by running a script termed GeneMark-Genesis that performed recursive application of GeneMark against the Synechocystis data and evaluated the probability scores for optimization. Based on the matrices thus generated, 752 of the 818 previously assigned ORFs (92%) were supported by GeneMark as likely coding sequences, of which 26 were predicted to start at more internal positions than previously assigned. In addition, 50 ORFs were newly identified as likely coding sequences, most of them being shorter than 300 bp. Thus, the procedure was proven to be very powerful to locate likely coding regions within the genomic sequence data of Synechocystis without having prior information concerning their similarity to the genes of other organisms. However, GeneMark did not predict 66 previously assigned ORFs as likely genes: 14 of them showed significant degrees of similarity to known genes and 10 others were found within IS-like elements. It seems that these genes, many of which appear to be exogenous origin, escaped detection by GeneMark as in the case of "class 3 (horizontally transferred) genes" of E. coli, which in turn suggests that genes of different phylogenetic origins might also be detected as such by modifying the matrices.

mel-18, a Polycomb group-related mammalian gene, encodes a transcriptional negative regulator with tumor suppressive activity

The mammalian mel-18/bmi-1 gene products share an amino acid sequence and a secondary structure, including a RING-finger motif, with the Drosophila Polycomb group (PcG) gene products Psc and Su(z)2, implying that they represent a gene family with related functions. As Drosophila PcG gene products are thought to function as transcriptional repressors by modifying chromatin structure, Mel-18/Bmi-1 might be expected to have similar activities. Here we have analyzed the function of mel-18 and found that Mel-18 acts as a transcriptional repressor via its target DNA sequence, 5'-GACTNGACT-3'. Interestingly, this binding sequence is found within regulatory or non-coding regions of various genes, including the c-myc, bcl-2 and Hox genes, suggesting diverse functions of mel-18 as the mammalian homolog of the PcG gene. We also demonstrate that mel-18 has tumor suppressor activity, in contrast to bmi-1, which has been defined as a proto-oncogene.

The effect of high-energy shock wave therapy combined with cisplatin on mouse hepatoma

It is well documented that high-energy shock waves (HESW) can produce antitumor effects in vivo and in vitro. Furthermore, because HESW can be focused on a limited area, this therapy is considered applicable to the treatment of localized cancer. In this study, we investigated the effects of HESW therapy combined with cisplatin (CDDP) on MH134 hepatoma in a mouse model. Tumor growth was inhibited by 1 mg/kg CDDP treatment in combination with 2,000 HESW administration, but not by 1 mg/kg CDDP treatment only. Moreover, the CDDP concentration in the tumor increased after HESW administration. The active oxygen induced by HESW was then investigated by the electron spin resonance system, and it was found that HESW generated hydroxy-radicals. As oxygen radicals have been reported to change cell membrane potential, it is supposed that active oxygen induced by HESW changes cell membrane permeability, and that CDDP is concentrated in the tumor. Therefore, the combined therapy with HESW and CDDP showed synergistic inhibitory effects on tumor growth.

Role of recruited neutrophils in interleukin-8 production in dog trachea after stimulation with Pseudomonas in vivo

Cell-free supernatant of Pseudomonas aeruginosa (PA) recruits neutrophils into the airways indirectly by inducing the production of chemotactic factors, including interleukin-8 (IL-8). PA products stimulate IL-8 expression selectively in surface airway epithelium, gland ducts, serous cells, and recruited neutrophils. To examine the relative contribution of neutrophils in IL-8 release in the airway lumen, we studied the effect of inhibition of neutrophil recruitment on IL-8 concentration in tracheal fluid after introduction of PA supernatant into the dog trachea in vivo. Tracheal superfusion with PA supernatant caused neutrophil recruitment and increased the IL-8 concentration in the tracheal lumen; NPC 15669 inhibited both effects. To study whether migration of neutrophils into the airway lumen per se induces their expression of IL-8, we compared effects of local introduction of IL-8 and of PA supernatant into the trachea on IL-8 expression in neutrophils recruited into the trachea. PA supernatant, but not exogenous IL-8 alone, induced IL-8 mRNA expression in neutrophils recruited into the trachea. To determine what product(s) of PA stimulate IL-8 expression in neutrophils, we examined neutrophils isolated from peripheral blood. PA supernatant induced IL-8 production in neutrophils, an effect reproduced by PA lipopolysaccharide and inhibited by polymyxin B. These results suggest that neutrophils recruited into the airway lumen play a major role in local IL-8 production in airways in response to bacteria such as PA, depending on the presence of stimuli such as lipopolysaccharide.

Endoscopic ultrasound-guided pancreatography: a case report

Endoscopic ultrasound-guided pancreatography was performed on a 48-year-old man with a diagnosis of pancreatic stone. A pylorus-preserving pancreaticoduodenectomy had been performed previously on this patient, approximately two years earlier, following the diagnosis of a tumor-forming pancreatitis. Endoscopic retrograde pancreatography and conventional ultrasound-guided percutaneous pancreatography had failed to yield a diagnosis. However, endoscopic ultrasound-guided pancreatography was performed successfully, delineating the pancreatic duct and a filling defect caused by intraductal calculi. Endoscopic ultrasound-guided pancreatography will be a potential alternative in cases when endoscopic retrograde pancreatography has failed or proved non-diagnostic.

Right hepatic lobe agenesis associated with bile duct carcinoma

A patient with obstructive jaundice was found to have bile duct carcinoma and right hepatic lobe agenesis. The diagnosis was made by computed tomography (CT), cholangiography, and angiography. Right hepatic lobe agenesis is a rare anomaly and has never been previously reported with bile duct carcinoma. CT cholangiography was critical in diagnosing the morphologic anomalies of the bile duct in this case.

Enhancement of the antitumor effect by combined use of high-energy shock waves and ATX-70

The antitumor effects of high-energy shock waves (HESW) in combination with ATX-70 [a gallium-porphyrin complex, 2,4-bis(1-decyloxyethyl)-Ga(III)-1,3,5,8-tetramethylporphyrin++ +-6, 7-dipropionyl diaspartic acid [sequence: see text] were investigated. In vitro, the cell damage to mouse MH134 hepatoma after HESW treatment was enhanced by adding ATX-70. In vivo, HESW and ATX-70 combination therapy inhibited cell growth. However, neither HESW treatment alone nor ATX-70 treatment alone inhibited cell growth. These results imply that the antitumor effects of HESW and ATX-70 combined therapy are caused by activation of ATX-70 by HESW.

Tautomycin: an inhibitor of protein phosphatases 1 and 2A but not a tumor promoter on mouse skin and in rat glandular stomach

Tautomycin isolated from Streptomyces spiroverticillatus is an inhibitor of protein phosphatases 1 and 2A. Tautomycin induced hyperphosphorylation of cytokeratin peptides in human keratinocytes (PHK 16-I cells) 30 times less strongly than did okadaic acid. Repeated applications of tautomycin (30 micrograms, 40 nmol/application) did not induce tumor promotion in a two-stage carcinogenesis experiment on mouse skin initiated with 7,12-dimethylbenz[a]anthracene, whereas okadaic acid (1 microgram, 1.2 nmol/application) as a control induced tumor promotion strongly. As for mucosa of rat glandular stomach, tautomycin induced ornithine decarboxylase 4 h after intubation into the stomach. The tumor-promoting activity of tautomycin was next studied in the glandular stomach initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Administration of tautomycin in the diet (1 mg rat-1 day-1), from week 9 to week 52 of the experiment, inhibited rather than enhanced tumor development in the glandular stomach initiated with MNNG. The percentages of tumor-bearing rats of the groups treated with MNNG plus tautomycin, MNNG alone, and tautomycin alone were 20.0%, 40.6%, and 0% respectively in week 52. The reason for the absence of tumor-promoting activity of tautomycin was studied in relation to tumor necrosis factor alpha (TNF alpha), an endogenous tumor promoter. We found that tautomycin neither enhanced TNF alpha mRNA expression in mouse skin nor induced TNF alpha release in a human stomach cancer cell line (KATO III cells), whereas okadaic acid did both. These results indicate that not all inhibitors of protein phosphatases are tumor promoters, and suggest that tumor promotion of the okadaic acid class of compounds is mediated by TNF alpha.

Immunotherapy for esophageal cancer. A randomized trial in combination with radiotherapy and radiochemotherapy. Cooperative Study Group for Esophageal Cancer in Japan

We investigated the effect of multimodal therapy in 187 patients with esophageal cancer. All patients were followed up over a period of 5 years. Among the 187 patients, 174 (93.1%) eligible patients with biopsy-proved esophageal squamous cell carcinoma underwent esophagectomy and were randomly assigned to receive radiotherapy (RT) with or without protein-bound polysaccharide (PSK), or RT plus chemotherapy (CT) with or without PSK. The 5-year survival rates of patients with RT, RT+PSK, RT+CT and RT+CT+PSK were 40.0%, 42.3%, 29.1% and 37.2%, respectively. There was a tendency for longer survival on PSK, but statistical significance was not reached (RT+CT group versus RT+CT+PSK group: log-rank and generalized Wilcoxon tests, P = .1930, P = .1034). However, Cox multivariate regression analysis indicated that postoperative therapy with or without PSK was the most significant prognostic factor for patients receiving RT+CT and for the eligible patients. These results indicate that PSK may have a beneficial effect on esophageal carcinoma when given in combination with CT+RT.

Molecular characterization of a tandem repeat, Afa family, and its distribution among Triticeae

We have characterized a so-called D genome specific repetitive DNA sequence (pAs1) of Aegilops squarrosa L. (2n = 14, genome DD) with respect to its DNA sequence and its distribution among Triticeae species. The clone consisted of three units of a repetitive DNA sequence of 336 or 337 base pairs, and was AT rich (65.2%). DNA analyses revealed the presence of the pAs1-like sequences in other genomes of Triticeae species, although the repetition was greatly (as much as 100-fold) variable among the genomes. The repetitive sequences from 10 diploid species were amplified using PCR with specific primers, and the sequential variability was analyzed by the digestion pattern obtained with five restriction enzymes. Since the AfaI site was the most conservatively present in the unit of the repetitive sequences, we named them "Afa family." The analysis clearly displayed the variation of the repetitive sequences regardless of the uniformity of the size of the amplified product. These results indicated that plural amplification events of these repetitive sequences happened independently in the genome evolution of Triticeae.

RS-22A, B and C: new macrolide antibiotics from Streptomyces violaceusniger. I. Taxonomy, fermentation, isolation and biological activities

Three novel 36-membered macrolide antibiotics, RS-22A, B and C produced by Streptomyces violaceusniger have been isolated. These antibiotics were purified from an acetone extract of the mycelia followed by butanol extraction, centrifugal partition chromatography and HPLC. RS-22A, B, C showed antimicrobial activity against fungi and Gram-positive bacteria.

[Anatomical analysis of small bronchial arteries in front of the trachea by 3D-CT and digital subtraction angiography: implications for esophageal cancer surgery]

To preserve blood supply to the trachea and bronchus in the surgical procedure for esophageal cancer, anatomical characteristics of small bronchial arteries which course in front of the trachea were analysed by three-dimensional computed tomography (3D-CT) and digital subtraction angiography (DSA). In the 3D-CT study using five mediastina, three dimensional images of the bronchial arteries were reconstructed after the injection of contrast medium into the intercostobronchial arteries. Thus the detailed vascular network of the course of the small bronchial arteries in front of the trachea could be delineated. In the DSA study using seven mediastina, through this network of bronchial arteries, the branches originating from the aorta and the arteries supplying the cranial portion of the trachea could be viewed. These results indicate that the bronchial arteries are connected by a vascular network in front of the trachea. Based on these detailed findings, it is considered critical to avoid damage to the intercostobronchial artery and also the network of bronchial arteries in order to preserve blood supply to the trachea and bronchus.

Inhibition of specific binding of okadaic acid to protein phosphatase 2A by microcystin-LR, calyculin-A and tautomycin: method of analysis of interactions of tight-binding ligands with target protein

Several groups have reported that okadaic acid (OA) and some other tight-binding protein phosphatase inhibitors including microcystin-LR (MCLR), calyculin-A and tautomycin prevent each other from binding to protein phosphatase 2A (PP2A). In this paper, we have introduced an improved procedure for examining to what extent the affinity of an enzyme for a labelled tight-binding ligand is reduced by binding of an unlabelled tight-binding, ligand to the enzyme. Using this procedure, we have analysed the dose-dependent reduction of PP2A binding of [24-3H]OA by addition of OA, MCLR, calyculin-A and tautomycin. The results indicate that the binding of the unlabelled inhibitors to the PP2A molecule causes a dramatic (10(6)-10(8)-fold) increase in the dissociation constant associated with the interaction of [24-3H]OA and PP2A. This suggests that OA and the other inhibitors bind to PP2A in a mutually exclusive manner. The protein phosphatase inhibitors may share the same binding site on the PP2A molecule. We have also measured values of the dissociation constant (Ki) for the interaction of these toxins with protein phosphatase 1 (PP1). For MCLR and calyculin-A, the ratio of the Ki value obtained for PP1 to that for PP2A was in the range 4-9, whereas it was 0.01-0.02 for tautomycin. The value of tautomycin is considerably smaller than that (0.4) calculated from previously reported Ki values.

Cloning and characterization of the hrpA gene in the terC region of Escherichia coli that is highly similar to the DEAH family RNA helicase genes of Saccharomyces cerevisiae

During the course of systematic nucleotide sequence analysis of the terC region of E.coli K-12 by using the ordered lambda phage clones, we found the presence of a gene, termed hrpA, that showed a high degree of sequence similarity to the PRP2, PRP16 and PRP22 genes of Saccharomyces cerevisiae. The products of these yeast genes are known to play their roles in mRNA splicing, and belong to a group of proteins collectively called the DEAH family. The hrpA gene is the first example of a DEAH family gene in prokaryotes. The N-terminal region of the protein it encodes contains conserved sequence stretches characteristic of an RNA helicase. Its molecular mass is calculated to be 146 kDa. Previously, a 135 kDa protein was identified by Moir et al. [J. Bacteriol. (1992) 174, 2102-2110] in this region which is most likely identical to that encoded by hrpA. The C-terminal region of the hrpA gene product seems to contain an RNA binding motif weakly resembling that of ribosomal protein S1 of E.coli. Disruption of the hrpA gene suggested that it is not essential for the growth of E.coli.

Rare association of human papillomavirus DNA with esophageal cancer in Japan

To examine whether human papillomavirus (HPV) DNA is associated with esophageal cancer, frozen and paraffin-embedded neoplasms of the upper aerodigestive tract, including esophageal cancer, were investigated. DNA obtained from frozen specimens and cell lines were analyzed by both polymerase chain reaction (PCR) and Southern blot hybridization. DNA from paraffin-embedded samples were analyzed strictly by PCR. DNA of HPV types 6 and 11 was detected in papillomas of the upper respiratory tract at > 50%. However, HPV DNA was infrequently detected in specimens from the upper digestive tract (31 esophageal cancers and 2 esophageal carcinoma--derived cell lines), even by PCR at a sensitivity of 0.1 copy number per cell. These results suggest that the etiologic significance of HPV infection in esophageal cancer is negligible.

Possible predictive markers of immunotherapy in esophageal cancer: retrospective analysis of a randomized study. The Cooperative Study Group for Esophageal Cancer in Japan

The aim of this report is to evaluate retrospectively the data from a prospective randomized study of 158 esophageal cancer patients who actually completed therapy with protein-bound polysaccharide P (PSK) and the 5-year survivals with and without raised alpha 1-antichymotrypsin and sialic acid levels to determine the value of these parameters in predicting effectiveness of immunotherapy. There was a significant difference in survival between the patients with and without PSK therapy. The survival of the radiochemotherapy plus PSK group treated for > 3 months was significantly better than that of the radiochemotherapy group. Among the patients with abnormal levels of alpha 1-antichymotrypsin and sialic acid, those who received PSK may have a significantly better survival than those without PSK. These results indicate that the preoperative serum levels of alpha 1-antichymotrypsin and sialic acid may possibly predict the effectiveness of immunotherapy using PSK.

High frequency of cancer patients with abnormal assembly of the T cell receptor-CD3 complex in peripheral blood T lymphocytes

Structural abnormality of T cell receptor (TCR)-CD3 complex on the cell surface was investigated in peripheral blood lymphocytes (PBL) from 55 cancer patients. In 24 of the 68 tests done on these patients, the CD3 zeta chain was not detected by immunoprecipitation with anti-CD3 epsilon monoclonal antibody (mAb), but was observed with anti-CD3 zeta mAb, suggesting that a high frequency of cancer patients possesses abnormal T cell receptor (TCR) complex in PBL. On the other hand, the total zeta chain was missing in several advanced cases. During follow-up of several patients, the zeta chain became undetectable after two or three months of cancer progression. It appears that immunosuppressive status can be monitored by analyzing the TCR-CD3 complex on the cell surface of PBL.

Flies in the group Cyclorrhapha use (3S)-3-hydroxyretinal as a unique visual pigment chromophore

In the class Insecta, retinal and 3-hydroxyretinal are used as chromophores of visual pigments, but the absolute structure of the 3-hydroxyretinal chromophore has yet to be clarified. This study investigates the chirality of 3-hydroxyretinal in the compound eyes of five representative orders of insects. In the orders Odonata, Hemiptera, Neuroptera and Lepidoptera, and suborders Nematocera and Brachycera of the Diptera, only (3R)-3-hydroxyretinal isomers were detected, but dipterans of the suborder Cyclorrhapha (higher flies) had the (3S)-11-cis enantiomer and a mixture of (3R)-all-trans and (3S)-all-trans 3-hydroxyretinal enantiomers; the ratio of the (3R) enantiomer to the sum of both enantiomers of the all-trans isomer was in the range 9-32%. Despite differences in feeding habits, including one species that is a butterfly parasite, all higher flies analysed to date share the same pattern of 3-hydroxyretinal enantiomers, making them a unique group with regard to the nature of the visual pigment chromophore.

Alcohol consumption and risk of esophageal cancer in Japan: a case-control study in seven hospitals

In a multi-center case-control study, we evaluated the risk of esophageal cancer in the Japanese population. All patients and controls were inpatients in the surgical departments of seven hospitals nationwide. Patients eligible for the study were those newly diagnosed as having primary esophageal cancer. One control per case was selected from among patients admitted to the same hospital, and 141 male pairs were analyzed using logistic regression analysis. The results showed dose-response relation between the risk of esophageal cancer and both the quantity (g/week) and frequency (times/week) of alcohol drinking (P value for trend = 0.0001). Although a statistically significant risk increase was shown among moderate to heavy smokers (15 < or = cigarette/day < 25) (odds ratio, 4.35:95% confidence interval, 1.81-10.49), the dose-response for cigarette smoking was unclear (P value for trend = 0.07). No combined effect of alcohol drinking and cigarette smoking was found. A frequent intake of fruit was associated with a decreased risk (P value for trend = 0.02). After adjustment for alcohol consumption, cigarette smoking and fruit intake were found not to be associated with the risk, whereas a preference for high-temperature food and drink showed a statistically significant positive association (P value for trend = 0.02). Drinkers who consumed shochu most frequently showed a three-fold increased risk over that for beer consumers, although the association disappeared after adjusting for the amount of alcohol consumed. The present results confirm alcohol intake and a preference for high-temperature food to be associated with an increased risk of esophageal cancer and show the amount of alcohol consumed, rather than the type of alcoholic beverage, to be the main risk determinant.

The yeast nuclear gene MRP-L13 codes for a protein of the large subunit of the mitochondrial ribosome

The nuclear gene MRP-L13 of Saccharomyces cerevisiae, which codes for the mitochondrial ribosomal protein YmL13, has been cloned and characterized. It is a single-copy gene residing on chromosome XI. Its nucleotide sequence was found to be identical to that of the previously reported ORF YK105. A comparison of the predicted protein sequence of the MRP-L13 gene product and the actual N-terminal amino-acid sequence of the isolated YmL13 protein indicated that the mature protein is preceded by a mitochondrial signal peptide of 86 amino-acid residues, which is the longest among all known mitochondrial ribosomal proteins of S. cerevisiae. No sequence similarity was found to any other ribosomal protein in the current databases. The transcription of MRP-L13 was found to be repressed in the presence of glucose. Its protein product is not strictly essential for mitochondrial functions, but disruption of the gene by insertion of LEU2 noticeably affected cellular growth on non-fermentable carbon sources.

Accelerated bone marrow recovery from radiation damage in etoposide-pretreated mice

PURPOSE

Etoposide inhibits the activity of Topoisomerase II, and possesses radiosensitizing effects on cultured cells. We showed that pretreatment of mice with etoposide 1 day before whole-body irradiation (WBI) had a protective effect against radiation-induced bone marrow death. The number of endogenous colony-forming units (CFU-S) surviving in WBI mice was significantly increased by pretreatment with etoposide. The purpose of the present study is to clarify mechanisms underlying the protective activity of etoposide against radiation-induced bone marrow damage.

METHODS AND MATERIALS

The spleen colony-forming cells (CFU-S) of femoral marrow were assayed by the method of Till and McCulloch. The proliferative state of CFU-S was assessed using the technique of Hodgson. The reduction in exogenous CFU-S after hydroxyurea injection was used to determine the fraction size of S-phase in CFU-S.

RESULTS

Etoposide pretreatment did not modify the cell survival parameters of exogeneous CFU-S when bone marrow cells were assayed immediately after WBI. Recovery of CFU-S in femoral marrow started earlier in mice receiving etoposide pretreatment than in the radiation alone group. Administration of hydroxyurea revealed that the accelerated recovery of CFU-S was due to an increased population of S phase cells, suggesting etoposide pretreatment shortened generation time of CFU-S.

CONCLUSIONS

The mechanism for the radioprotection appears to be accelerated proliferation of survived bone marrow cells rather than a change in cellular sensitivity to radiation.

Signaling pathway other than phosphatidylinositol turnover is responsible for constant expression of c-myc gene in primary cultures of rat hepatocytes

We investigated signal transduction pathways involved in c-myc activation, using rat hepatocytes in primary culture. c-Myc mRNA was constantly expressed in the cultured hepatocytes regardless of the conditions present. When the expression was examined in the presence of various agents modulating intracellular signals, isoflavonoids (genistein, psi-tectorigenin, and orobol) significantly decreased c-myc mRNA levels, in a dose dependent manner. However, genistein did not decrease Li+ induced inositol phosphate accumulation using [3H]inositol-labeled cultured hepatocytes. In addition, we have shown that these isoflavonoids increase cytoplasmic free Ca2+, when measured using aequorin-loaded hepatocytes. In light of these observations, the persistent basal level of c-myc expression seems to be maintained by mechanisms other than phosphatidylinositol turnover.

Stimulation by menthol of Cl secretion via a Ca(2+)-dependent mechanism in canine airway epithelium

1. To investigate the effect of menthol on airway epithelial ion transport function, we studied the bioelectrical properties of canine cultured tracheal epithelium by Ussing's short-circuit technique in vitro. 2. Addition of menthol (10(-3) M) to the mucosal but not the submucosal solution increased the short-circuit current (Isc) from 6.2 +/- 0.9 to 14.0 +/- 2.2 microA cm-2 (P < 0.001), and this effect was accompanied by increases in transepithelial potential difference and conductance. The response was dose-dependent, with the maximal increase from the baseline value and the concentration required to produce a half-maximal effect (EC50) being 6.4 +/- 0.9 microA cm-2 (P < 0.001) and 40 microM, respectively. 3. Other cyclic alcohols, including menthone and cyclohexanol, had no effect on the electrical properties. 4. The menthol-induced increase in Isc was not altered by pretreatment of the cells with amiloride, indomethacin, or propranolol but was abolished by diphenylamine-2-carboxylate, furosemide or substitution of Cl with iodide in the medium. 5. Menthol (10(-3) M) increased cytosolic levels of free calcium ([Ca2+]i) from 98 +/- 12 to 340 +/- 49 nM (P < 0.01) in fura-2-loaded tracheal epithelium but did not affect the intracellular adenosine 3',5'-cyclic monophosphate content. 6. These results suggest that menthol stimulates Cl secretion across airway epithelium, probably through a Ca(2+)-dependent mechanism, and might thus influence mucociliary transport in the respiratory tract.

Phosrestin I undergoes the earliest light-induced phosphorylation by a calcium/calmodulin-dependent protein kinase in Drosophila photoreceptors

Activation of PI-PLC initiates two independent branches of protein phosphorylation cascades catalyzed by either PKC or Ca2+/calmodulin-dependent protein kinase (CaMK). We find that phosrestin I (PRI), a Drosophila homolog of vertebrate photoreceptor arrestin, undergoes light-induced phosphorylation on a subsecond time scale which is faster than that of any other protein in vivo. We determine that a CaMK activity is responsible for in vitro PRI phosphorylation at Ser366 in the C-terminal tryptic segment, MetLysSer(P)IleGluGlnHisArg, in which Ser(P) represents phosphoserine366. We also demonstrate that Ser366 is the phosphorylation site of PRI in vivo by identifying the molecular species resulting from in-gel tryptic digestion of purified phospho-PRI using HPLC-electrospray ionization tandem quadrupole mass spectroscopy. From these data, we conclude that the CaMK pathway, not the PKC pathway, is responsible for the earliest protein phosphorylation event following activation of PI-PLC in living Drosophila photoreceptors.

Clear cell carcinoma of salivary glands: immunohistochemical evaluation of clear tumor cells

A total of 14 cases of clear cell carcinoma of salivary glands were evaluated by immunohistochemical methods using monoclonal antibodies to cytokeratin (K1.1 and K8.12), vimentin, S-100 alpha and beta subunits, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), MAM-3 and MAM-6 antigens and proliferating cell nuclear antigen (PCNA), as well as polyclonal antibodies to lysozyme (Ly), lactoferrin (la) and Alpha-1-antichymotrypsin (alpha 1-Ach). Histopathologically, the carcinoma was characterized by round or polygonal tumor cells with cytoplasm that does not stain with hematoxylin and eosin, nuclei with little pleomorphism and few or no mitotic figures, and growing in solid sheets, small nests or cords with collagenous stroma. Cytokeratin KL1 and K8.12 was present in few tumor cells with almost negligible to strong reaction in all cases, vimentin in 6, GFAP in 5 cases with multiple-expression of cytokeratin K8.12, vimentin and GFAP in 5 cases. S-100 protein immunoreactivity was the most prominent feature with more intense reaction of S-100 beta than S-100 alpha subunit. NSE reactivity was seen in 6 cases. Ly, La, a1-ch, MAM-3 and MAM-6 antigens were localized in clear cells with various reaction intensities. The authors conclude that the clear tumor cells in clear cell carcinoma of salivary glands are not myoepithelial in origin but epithelial or neuroectodermal/neural crest in origin, showing ductal differentiation at the immunohistochemical level.