Videothoracoscopic treatment of spontaneous pneumothorax

Thoracoscopic surgery has been well accepted as a treatment for spontaneous pneumothorax and other intrathoracic diseases. Seventy-four patients with primary or secondary pneumothorax underwent thoracoscopic operation in this hospital. There was no postoperative mortality or major morbidity. Only two (2.7%) patients developed recurrent pneumothorax postoperatively, but this never reappeared after using bullae resection and mechanical pleurodesis in place of electroablation only at an earlier period. Three patients had residual pleural effusion or air space, and two patients had persistent air-leak postoperatively; all of them recovered after conservative treatment. The mean operation time, intensive care unit stay, and total hospital stay were decreased significantly when compared with open thoracotomy. The low recurrence rate and shorter hospital stay also made this procedure much superior to tube thoracostomy and chemical pleurodesis only. Approaches to make working ports, bullectomy, and pleurodesis are also discussed here. We concluded that thoracoscopic surgery is highly effective and minimally invasive for patients with spontaneous pneumothorax, but may not be suitable for patients with generalized emphysematous change of lungs or dense adhesion of the pleural spaces.

Immunologic and physicochemical studies of Bermuda grass pollen antigen BG60

BACKGROUND

In a previous study we showed that antigen BG60 of Bermuda grass pollen contains isoallergens. Because the yield of purified isoallergens was low when a chromatofocusing technique was used, it was difficult to carry out further studies, such as determination of carbohydrate composition and structure.

OBJECTIVE

The aim of this study was to establish a procedure to purify antigen BG60 proteins as a group and to characterize this group's physicochemical and immunologic properties.

METHODS

A combination of chromatographic techniques (ion-exchange, gel filtration, blue gel affinity, and reverse-phase high-performance liquid chromatography) was used for the purification of BG60. Immunoblot and ELISA techniques were used to study BG60-specific IgE and IgG antibodies in patients' sera. The role of the carbohydrate moiety in antigenicity and allergenicity was examined with monoclonal antibodies and allergic sera by using periodate-treated BG60. Its carbohydrate composition was analyzed by high-performance anion-exchange chromatography with a pulsed amperometric detector.

RESULTS

Homogeneity of BG60 was demonstrated by a single sharp peak in reverse-phase high-performance liquid chromatography, a single band in sodium dodecylsulfate-polyacrylamide gel electrophoresis, and only one band stained by anti-BG60 monoclonal antibody. BG60-specific IgE and IgG antibodies were shown to be present in allergic sera. Six plant lectins were found to react with BG60. On periodate treatment, BG60 reduced binding toward its monoclonal antibody and human IgE and IgG. Carbohydrate composition analysis showed that BG60 contains three kinds of sugars: mannose, N-acetylglucosamine, and fucose (in a ratio of approximately 3:2:1) and a minute amount of xylose. The carbohydrate content is approximately 7.5%, and peptide content is about 92.5%.

CONCLUSION

A procedure was established for the purification of a large quantity of the BG60 antigen. The results suggest that the carbohydrate moiety of antigen BG60 may play an important role in the immune response.

Use of the silicone tracheal T-tube for tracheostenosis or tracheomalacia

BACKGROUND

Tracheobtenosib and tracheomalacia are trivial diseases. The conventional choice of managements with tracheostomy, either temporary or long-term usage, can only partially resolve the problems of airway obstruction. Silicone tracheal T-tube presents a substitute for it.

METHODS

We present 5 patients with tracheostenosis or tracheomalacia managed with nine procedures of long silicone Montgomery T-tube prothesis between 1984 and 1994 in VGH-Taipei. The primary diagnosis included tracheal injury (2), postintubation tracheal stenosis (2), and stenosis due to endotracheal tuberculosis (1). Three patients received a long segmental T-tube for permanent endotracheal stenting and the other two patients used T-tube insertion for temporary stenting of the trachea for 7 and 11 months, respectively, with satisfactory results.

RESULTS

All patients got immediate benefit from the prothesis in respiration with simple postoperative care. Two patients with temporary T-tube placement had it successfully removed in 7 and 11 months, respectively. Placement of the T-tube for subglottic stenosis also protected the function of phonation. The tracheal T-tube restored airway patency reliably with good long-term results and could be the preferred management of chronic upper airway obstructive disease not amenable to surgical repair. The most common complication was airway obstruction caused by either granulations or sticky mucoid substance. Three patients and six tubes (60%) developed granulation obstruction and the average duration of granuloma formation was 7.7 months. Laser phototherapy or surgical intervention, such as tracheoplasty, with change of the T-tube was carried out for granuloma obstruction.

CONCLUSIONS

T-tube is a good endoprothesis for tracheostenosis and tracheomalacia with minimal complication for cases of long tracheostenosis or complex tracheal injury.

Recurrent focal palmar peeling

Recurrent focal palmar peeling, previously known as keratolysis exfoliativa, is an idiopathic condition characterized by chronic palmar and occasionally plantar peeling. It can be exacerbated by environmental factors, and may be misdiagnosed as chronic contact dermatitis. Accurate diagnosis is from the history and examination. It is supported by a negative patch test result. Three cases of recurrent focal palmar peeling are presented, of which two were misdiagnosed as chronic dermatitis. Although there are few references on recurrent focal palmar peeling, it is likely to be a common condition that rarely presents to dermatologists because it is largely asymptomatic. A correct diagnosis is essential due to the social, occupational and legal implications if misdiagnosed.

Nucleolar organizer regions as a prognostic factor in surgically treated lung cancer patients

The prognostic value of the number of nucleolar organizer regions (NORs) (DNA loops in the nucleus) in tumor cells from various kinds of malignancies has been widely studied in recent years. During the period 1989 to 1992, a total of 73 primary lung tumors was examined for the number of NORs by silver staining AgNOR proteins on the stump smear of resected specimens in this hospital. The relations of the mean number of AgNOR per cell with other factors such as sex, age, habit of smoking, performance status, tumor location, tumor size, pathological stage, histological type, degree of differentiation, and whether histologically vascular or lymphatic invasion were analysed. It was found that the mean number of AgNOR was significantly different between positives and negatives of histologically vascular or lymphatic invasion (6.4 +/- 0.4 vs 5.5 +/- 0.2) (p < 0.05). Both single and multiple-variate analysis of patient survival revealed that the mean number of AgNOR was a significant prognostic factor, as were pathological stage, histological type, and performance status of the patient. Patients with a higher mean number of AgNOR (> 7) had a significantly worse prognosis compared with those with less AgNOR (< or = 7) (median survival 28 versus 43 months) (p < 0.05). It was concluded that the mean number of AgNOR of tumor cells is a significant prognostic factor in surgically treated lung cancer patients.

Transfer of Man9GlcNAc to L-fucose by endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae

We have reported that transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (endo-A) can be enhanced to near completion using GlcNAc as an acceptor in a medium containing 30% acetone (Fan J-Q, Takegawa K, Iwahara S, Kondo A, Kato I, Abeygunawardana C, Lee YC (1995) J Biol Chem 270: 17723-29). In this paper, we found that the endo-A can also transfer an oligosaccharide, Man9GlcNAc, to L-Fuc using Man9GlcNAc2Asn as donor substrate in a medium containing 35% acetone. The transglycosylation yield was greater than 25% when 0.2 M L-Fuc was used as acceptor. The transglycosylation produce was purified by high performance liquid chromatography on a graphitized carbon column and the presence of L-Fuc was confirmed by sugar composition analysis and electrospray mass spectrometry. Sequential exo-glycosidase digestion of pyridyl-2-aminated transglycosylation product, Man9GlcNAc-L-Fuc-PA, revealed that a beta-anomeric configuration linkage was formed between GlcNAc and L-Fuc. The GlcNAc was found to be 1,2-linked to L-Fuc by two methods: i) collision-induced decomposition on electrospray mass spectrometry after periodate oxidation, reduction and permethylation of Man9GlcNAc-L-Fuc; and ii) preparation of Man9GlcNAc-L-Fuc-PA, its periodate oxidation and reduction, followed by hydrolysis and HPLC analysis. Thus, the structure of the oligosaccharide synthesized by endo-A transglycosylation was determined to be Man9GlcNAc beta (1,2)-L-Fuc. Methyl-beta-L-fucopyranoside, L-Gal are also acceptors for the enzymic transglycosylation. However, transglycosylation failed when methyl alpha-L-fucopyranoside, D-Fuc and D-Gal were used. These results indicate that the endo-A requires not only 3-OH and 4-OH to be equatorial but also a 4C1-conformation or equivalent conformation of the acceptor to perform transglycosylation.

Evaluation of therapeutic regimens for the treatment of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is currently considered the most important exogenous factor in the genesis of gastritis and peptic ulcer disease. However, the optimum regimen for the eradication of H. pylori remains unclear. The purpose of this study was to evaluate the eradication rate of H. pylori, the side effects, and the patients' compliance with regard to various drug regimens. We also analyzed factors influencing the eradication of H. pylori. One hundred and eighty patients were included and divided into four groups: 42 patients (Group I) received tripotassium dicitrato bismuthate (240 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; 55 patients (Group 2) received omeprazole (20 mg b.i.d.) and amoxicillin (1000 mg b.i.d.) for 14 days; 36 patients (Group 3) were treated with omeprazole (20 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; and 47 patients (Group 4) received omeprazole (20 mg q.d.) and amoxicillin (500 mg t.i.d.) for 14 days and then tripotassium dicitrato bismuthate (240 mg b.i.d.) and nizatidine (150 mg q.d.) for 14 days. The diagnosis of H. pylori was made by histology. The eradication of H. pylori was defined both by histology (H&E and Giemsa stain) and by rapid urease test (CLOR) showing negative for H. pylori 4 weeks after the completion of therapy. Of the 180 patients, 95 patients had non-ulcer dyspepsia, 40 patients had gastric ulcer and 45 patients had duodenal ulcer. The eradication rate of H. pylori was highest (89.3%) in Group 3, as compared with Group 1 (68.9%), Group 2 (65.4%), and Group 4 (48.9%). The eradication rate was significantly higher in Group 3 than in Groups 2 and 4 (p < 0.05). There was no significant difference in the eradication rate among clinical diagnosis, sex and age. But, in the conventional triple therapy (Group 1), the eradication rate was higher in male (78.6%) than in female (46.2%). The side effects in order, were nausea (22.1%), dizziness (19.5%), abdominal pain (11.6%) and diarrhea (97%), and there was no difference among the drug regimens. The compliance of the patients was good (more than 80% irrespective of drug regimen). On the basis of these findings, the side effects of the drugs seemed minimal, and the compliance of patients was good irrespective of the drug regimen. In conclusion, the triple therapy with omeprazole, metronidazole and amoxicillin was the most effective regimen and could be recommended for H. pylori eradication.

Changes in ocular refraction and its components among medical students--a 5-year longitudinal study

PURPOSE

Myopic progression has been noted, especially during the period of puberty. It is interesting to investigate whether myopia will progress after the age of puberty and at what rate the changes in ocular components occur during its progression.

METHODS

A 5-year longitudinal study was made of refraction and its components among 345 National Taiwan University medical students (690 eyes). The examinations included corneal curvature and cycloplegic refraction measured by auto-refractor and retinoscopy, and axial length measurement with A scan ultrasonography. The same procedures and instruments were used again after 5 years.

RESULTS

The myopic prevalence increased from 92.8 to 95.8%; 21 new cases of myopia developed in the 5 years. The mean refractive error significantly increased from -4.26 +/- 2.66 D of freshmen to -4.94 +/- 2.70 D of clerks. The change in refractive error at the 5-year follow-up was 0.70 +/- 0.65 D more myopic for males and 0.54 +/- 0.64 D for females. The main change in the ocular components was in axial length, which increased from 25.54 to 26.05 mm in males and from 24.60 to 24.95 mm in females. Other optical components-including corneal curvature, anterior chamber depth, lens thickness-all remained relatively unchanged from the initial values.

CONCLUSIONS

Myopia can progress after the age of puberty, but at a slower rate than during childhood. Axial elongation of the eyeball is the main component that changes in myopic progression.

In vitro study for staining and toxicity of rose bengal on cultured bovine corneal endothelial cells

It has recently been reported that rose bengal (RB) is actually not a vital dye and that it has an intrinsic toxic effect. Therefore, we conducted a study to determine its staining capability and the presence of intrinsic toxicity. We also examined its effects on the proliferation of cultured bovine corneal endothelial cells. The cells stained despite short exposure (1 s) to rose bengal under a fluorescein photomicroscope. The cell nucleus stained first, followed by the cytoplasm; the intensity was directly dependent on the exposure time. Although the entire cell layer did not stain at an RB concentration of 0.001%, the cell layer stained diffusely above a concentration of 0.01%. At a 5% concentration, areas of cellular detachment and lysis were noted. The degree of cellular change was directly proportional to the concentration of RB and the exposure time. Cellular damage included cell swelling, intracytoplasmic vacuole formation, cell detachment, and lysis. The presence of light augmented the toxic effect of RB on cultured endothelial cells and was statistically more significant than RB's intrinsic toxic effect. Exposure to RB concentrations > 0.01% induced statistically significant concentration-dependent inhibition of cell proliferation. These results suggest that rose bengal may not actually be a vital dye on cultured bovine corneal endothelial cells and that it has intrinsic inhibitory and toxic effects with additional phototoxic effects on corneal endothelial cells. Furthermore, cell proliferation was markedly inhibited after exposure to RB.

A fluorometric assay of ceramide glycanase with 4-methylumbelliferyl beta-D-lactoside derivatives

4-Methylumbelliferyl 6'-O-benzyl-beta-D-lactoside (6'Bn-MU-Lac) and some related compounds were synthesized via different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6'Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, the K(m) value is 0.232 mM at pH 5.

Sequence analysis of the 5'-flanking region of the gene encoding human N-acetylglucosaminyltransferase III

We have isolated and characterized the immediate (1651 bP) 5'-flanking region of the gene (GnT-III) encoding N-acetylglucosaminyltransferase III (GnT-III) from a human placental genomic library. Analysis of promoter elements shows a similarity to the 5'-flanking region of murine 1,4-galactosyltransferase. The sequence lacks obvious TATA elements and CCAAT boxes; however, putative regulatory sites, including 2 potential cAMP-response regulatory elements (CRE), 11 insulin-response element consensus sequences (IRE), 7 potential AP-2 binding sites, 2 SP1 consensus sequences (GC boxes) and 2 sequences similar to the half-palindromic glucocorticoid-responsive element (GRE), are present.

Circadian rhythm in the Ca(2+)-inhibitable adenylyl activity of the rat striatum

In the present study, we demonstrate that the Ca(2+)-inhibitable adenylyl cyclase (AC) activity in the striatum exhibits a daily oscillation with a peak occurring around 10:00 h. A circadian fluctuation of the AC activity evoked by an A2a adenosine-selective agonist was also observed. Intrastriatal injection of an A2a-selective adenosine agonist or antagonist during the interval in which the Ca(2+)-inhibitable AC activity was at its peak resulted in a more significant alteration of locomotor activity than those observed at a later interval. The marked circadian variation in the Ca(2+)-inhibitable AC activity in the striatum appears to cause a circadian fluctuation in the action of at least one neuromodulator.

Endothelin-1 concentrations and optimisation of arterial oxygenation and venous admixture by selective pulmonary artery infusion of prostaglandin E1 during thoracotomy

In order to improve arterial oxygenation and venous admixture during one lung ventilation, the effect of selective infusion of prostaglandin E1 into the pulmonary artery of the ventilated lung was investigated in 12 adult patients undergoing thoracotomy. Patients' bronchi were intubated with a Mallinckrodt bronchial tube and ventilated with 66% oxygen in air. Cardiopulmonary factors such as systemic and pulmonary arterial pressures, pulmonary vascular resistance, blood gas analyses, cardiac output and airway pressure were measured before and during one-lung ventilation; venous admixture (Qs/Qt) was calculated. Serial blood samples were taken from the pulmonary artery of the ventilated lung for endothelin-1 estimation. One lung ventilation reduced the mean PaO2 from 42.1 (2.3) kPa to 11.8 (1.4) kPa (p < 0.001) and increased Qs/Qt from 10.8 (3.2)% to 39.2 (4.7)% (p < 0.001). Pulmonary vascular resistance also increased from 167 (24) dyne.s.cm-5 to 262 (38) dyne.s.cm-5 (p < 0.05) with a corresponding increase of plasma endothelin-1 (p < 0.05). After 30 min of one lung ventilation, PGE1 was infused continuously into the pulmonary artery of the ventilated lung at a rate which increased incrementally from 0.04-0.10 micrograms.kg-1.min-1. PaO2 increased to 20.7 (2.6) kPa (p < 0.01) and Qs/Qt decreased to 30.6 (3.5)% (p < 0.05). During the infusion, pulmonary vascular resistance reduced to 173 (30) dyne.s.cm-5 (p < 0.01). The plasma endothelin-1 concentration reached a plateau between the end of one lung ventilation (before closing the thorax) and 6 h postoperatively. This correlated inversely with the pre-operative forced expiratory volume in one second (r = -0.68, p < 0.005), declining to normal values 72 h after operation. The selective infusion of PGE1 into the pulmonary artery of the ventilated lung corrected pulmonary vasoconstriction and improved both arterial oxygenation and venous admixture during one lung ventilation for thoracotomy.

Cutaneous metastasis of lung cancer: an ominous prognostic sign

BACKGROUND

Cutaneous metastases in primary lung cancer rarely occurs in comparison with other organ involvement. Because of the absence of any uniform or pathognomic feature, they are often mistaken as a variety of benign lesions so that the outcome is extremely different. In this study, sixty-three cases of lung cancer with cutaneous metastases were retrospectively analyzed to determine the clinical pictures and length of survival.

METHODS

Retrospective analyses were performed for 5539 cases of proven lung cancer collected at the Cancer Treatment Center in Veterans General Hospital-Taipei during the period from January 1984 to May 1994. Seventy-two cases were documented cutaneous metastases. Nine of them were excluded due to inadequate medical records on clinical course.

RESULTS

Group A included the majority (48/63, 76.2%) of patients who had primary lung cancer with subsequent cutaneous metastases. The other 15 patients with cutaneous metastases as the initial presentations were classified as group B. (15/63, 23.8%). There were four major clinical presentations; solitary nodules, cluster of nodules, erythematous papule and bulging mass. Solitary nodule was the most frequent pattern (41/63 65.1%), ranging in size from 0.5 x 0.5 cm to 25 x 15 cm in surface area. The chest wall and abdominal wall were the regions most likely to develop cutaneous metastases. Metastatic lesions were occasionally found over the scrotum, lip and perianal region. Adenocarcinoma was the predominant cell type of cutaneous spread (25/63, 39.7%). The survival after diagnosis of cutaneous metastasis ranged from 3 weeks to 14 months, without significant difference between two groups of patients. Twenty-two patients (35%) survived no more than one month. The median survival was 3 months.

CONCLUSIONS

Cutaneous metastasis, as observed in our study, is an ominous sign indicating a poor prognosis with imminent death. Physicians should be alert to its characteristics and prognostic significance.

p53 protein expression in extrahepatic bile duct cancer

p53 mutations, a tumor suppressor gene located on chromosome 17p, are the most common genetic alterations found in human cancers. Although the p53 expression or mutation has been investigated in a variety of cancers there have been very few studies in extrahepatic bile duct cancers. In this study, we investigated the immunohistochemical expression of p53 in formalin fixed paraffin embedded archival specimens of 36 extrahepatic bile duct cancers in which p53 expression was found in eighteen (50%) cases. There was no significant difference in age, gender, size of tumor, histologic grade, extent of tumor involvement, lymph node metastasis and tumor resectability according to p53 immunoreactivity. Comparison of survival duration according to p53 expression showed no significant difference. In conclusion, we reported 50 percent of p53 expression in extrahepatic bile duct cancers by immunohistochemical staining and we found no prognostic significance of p53 expression in dinicopathologic parameters.

Characterization of the rat A2a adenosine receptor gene

To understand the molecular basis for the regulation of rat A2a adenosine receptor (A2a-R) expression, we have characterized the rat A2a-R gene and defined its promoter regions. Through a combination of restriction mapping and sequence analysis, we have demonstrated that the rat A2a-R gene is composed of two exons interrupted by a 7.2-kb intron. Primer extension and RNase protection on RNA isolated from PC12 cells suggested that the A2a-R gene encoded two clusters of alternative transcripts. The most upstream transcription start site was designated as +1. The sequence of the proximal 1.5 kb of 5'-flanking region demonstrated no potential TATA box, CCAAT box, or initiator element in the appropriate location. Varying lengths of 5'-flanking regions were inserted into a transient expression vector (pGL2-basic), which contained bacterial luciferase as the reporter gene, to determine its promoter region(s) in PC12 cells, CHOP cells, and C6 cells. Consistent with two clusters of transcription start sites, two independent functional promoter regions (designated P1, -67/-1; and P2, +272/+304) for the rat A2a-R gene were identified. Although both promoters are in use in PC12 cells, only P2 is active in CHOP cells, indicating possible cell line-specific usage of these two promoters.

Hydrophobic alkyl headgroups strongly promote membrane curvature and violate the headgroup volume correlation due to "headgroup" insertion

The ability of lipid aggregates to form planar bilayers, rather than highly curved micellar or inverted structures, is dependent on the relative geometries of the headgroup and hydrocarbon regions. The headgroup volume approach to lipid structure provided a quantitative link between a lipid's headgroup size and its ability to promote curved, inverted hexagonal (H(II)) structures in a phosphatidylethanolamine (PtdEtn) matrix [Lee et al. (1993) Biophys. J. 65, 1429-1432]. Phosphatidylalkanols (PtdAlks) are shown here to promote curvature with a potency that far exceeds and a chain length dependence contrary to the expectations of the headgroup volume approach, suggestive of an atypical alkyl "headgroup" conformation. A homologous series of 3-substituted triacylglycerols (TAGs), for which 3-acyl "headgroup" insertion is established, exhibits a chain length dependence similar to the PtdAlks, evidence that the deviation is of common origin. The potency of the TAGs to promote curvature is unprecedented, and the onset of saturation, which parallels the dramatic promotion of curvature, occurs at mole fractions as low as 0.0025. The potency of the PtdAlks or TAGs to promote curvature exceeds that of all mammalian phospholipids examined. Thermodynamic analysis implicates the enthalpic curvature stress imparted upon the membrane matrix as the dominant energetic factor. The imparted stress ranges from -930 J mol(-1) for phosphatidylcholine to +7.5 kJ mol(-1) for 3-palmitoyl TAG. The results affirm the geometric considerations of membrane structure and indicate that alkyl headgroups tend to insert into the bilayer and increase the enthalpic curvature stress within the membrane.

Mucin mRNA expression in lung adenocarcinoma cell lines and tissues

The expression pattern of mucin genes was studied in 7 lung adenocarcinoma cell lines (CL1, CL2, CL3, NCL2, PC9, PC13, PC14) and 12 lung adenocarcinoma tissues. CL1 and PC13 are poorly differentiated cell lines with low mucin glycoprotein production. The other 5 cell lines are well differentiated and produce a higher amount of mucins. Total RNA was extracted from these cell lines. Northern blot analysis was performed by hybridization with specific antisense oligonucleotide probes recognizing mucin-specific tandem repeats of 4 mucin genes (MUC1, MUC2, MUC3, MUC4). RT-PCR was carried out to amplify the 3' and 5' nonrepetitive coding regions of MUC1 and the 5' nonrepetitive coding region of MUC2. All these cell lines expressed MUC1, MUC2, and MUC4 mRNA but in variable mounts. The poorly differentiated cell lines (CL1 and PC13) had a relatively low level of expression of MUC1, MUC2, MUC3 and MUC4. RT-PCR, with primers amplifying the MUC1 nonrepetitive coding region 5' end, 293 bp, and the 3' end, 522 bp, as well as the MUC2 nonrepetitive 5' coding region, 308 bp, revealed the presence of MUC1 and MUC2 mRNA in all the cell lines. Sequence analysis of the PCR products were very homologous, similar to previously published MUC1 and MUC2 cDNA sequences. The expression pattern of mucin genes is consistent with that of mucin glycoproteins as studied using biochemical and immunological methods. Northern blotting and RT-PCR analysis in 12 lung adenocarcinoma tissues with various grades of differentiation (6 poorly differentiated adenocarcinomas and 6 moderately to well-differentiated adenocarcinomas) showed heterogeneous expression of the 4 mucin genes in tissues without clear correlation with the differentiation grade. Therefore the clinical implications of the differential expression of the mucin genes need further investigation.

Efficient production of Thermus protease aqualysin I in Escherichia coli: effects of cloned gene structure and two-stage culture

The DNA sequence encoding Thermus protease aqualysin I was inserted downstream from a bacteriophage T7 promoter in an expression vector. In the T7 expression system, using a strain lacking an F' episome, aqualysin I was produced in soluble form without chemical induction. The deletions of part (30 amino acid residues) or all (105 residues) of the C-terminal pro-sequence from the C terminus significantly affected both cellular growth and the production of the enzyme. Complete deletion adversely affected both. In contrast, the 30-residue deletion markedly improved productivity by approximately four times compared to non-deletion, and shortened the time needed for the activation of a precursor to active enzyme. The concentration of inducer isopropyl beta-D-thiogalactopyrano-side (IPTG) was varied to examine its effects, and it was found that a low concentration of IPTG improved aqualysin I production. To avoid the inhibitory effects of acetic acid accumulation in the culture medium, the use of other carbon sources besides glucose was examined. When cells were cultivated with glycerol, the acetic acid level remained relatively low, and both good cellular growth and a high level of production were attained. The aqualysin I productivity for a fed-batch culture using two carbon sources, glucose and glycerol, reached more than 150 kU/ml enzymatically active aqualysin I.

Development of colonic and pancreatic endocrine tumours in mice expressing a glucagon-SV40 T antigen transgene

We report the histological, immunohistochemical and ultrastructural changes in mice containing a chimeric glucagon-simian virus 40 T antigen (SV40Tag) gene. Transgene expression was detected in endocrine cells of pancreas, small and large intestine. Hyperplasia of glucagon-containing cells developed in pancreas and large bowel by gestational day 19. In large bowel, hyperplastic cells increased in number postnatally and invasive carcinomas were identified at 4 weeks; several animals had lymph node metastases. In contrast, no pathology was detected in the small bowel in any of the transgenic mice. Colonic tumours expressed SV40Tag, proglucagon-derived peptides and peptide YY (PYY); scattered cells contained cholecystokinin or glycoprotein hormone alpha-subunit. Somatostatin or serotonin was also detected in some tumours. By electron microscopy, the colonic tumours retained features of endocrine differentiation, but secretory granules were smaller than those of non-tumorous intestinal glucagon-producing L cells. In postnatal pancreas, atypical cells containing SV40Tag and glucagon were initially clustered at the periphery of islets; this atypical hyperplasia progressed to neoplasia by 11-12 weeks. Some neoplastic pancreatic cells contained glucagon, PYY or vasoactive intestinal peptide immunopositivity, but most were negative for all peptides; they contained immunoreactivity for tyrosine hydroxylase and by electron microscopy, pancreatic tumour cells had neuronal features. Pancreatic polypeptide was not detected in the non-tumorous islets of transgenic animals. This line of transgenic mice provides a model for the analysis of endocrine tumour progression in the gut and pancreas.

Sugars act as signal molecules and osmotica to regulate the expression of alpha-amylase genes and metabolic activities in germinating cereal grains

The molecular mechanisms that initiate and control the metabolic activities of seed germination are largely unknown. Sugars may play important roles in regulating such metabolic activities in addition to providing an essential carbon source for the growth of young seedlings and maintaining turgor pressure for the expansion of tissues during germination. To test this hypothesis, we investigated the physiological role of sugars in the regulation of alpha-amylase gene expression and carbohydrate metabolism in embryo and endosperm of germinating rice seeds. RNA gel blot analysis revealed that in the embryo and aleurone cells, expression of four alpha-amylase genes was differentially regulated by sugars via mechanisms beyond the well-known hormonal control mechanism. In the aleurone cells, expression of these alpha-amylase genes was regulated by gibberellins produced in the embryo and by osmotically active sugars. In the embryo, expression of two alpha-amylase genes and production of gibberellins were transient, and were probably induced by depletion of sugars in the embryo upon imbibition, and suppressed by sugars influx from the endosperm as germination proceeded. The deferential expression of the four alpha-amylase genes in the embryo and aleurone cells was probably due to their markedly different sensitivities to changes in tissue sugar levels. Our study supports a model in which sugars regulate the expression of alpha-amylase genes in a tissue-specific manner: via a feedback control mechanism in the embryo and via an osmotic control mechanism in the aleurone cells. An interactive loop among sugars, gibberellins, and alpha-amylase genes in the germinating cereal grain is proposed.