Non-diabetic renal disease in patients with non-insulin dependent diabetes mellitus

The diagnosis of diabetic nephropathy (DN) is almost always based on clinical grounds. The diagnosis is supported by a long history of diabetes, evidence of target organ damage and proteinuria preceding azotemia. The validity of this clinical approach is well established in insulin dependent diabetes mellitus but not in non-insulin dependent diabetes mellitus (NIDDM). It is thus important to determine which patients with NIDDM accompanied by non-diabetic renal disease (NDRD) should have a biopsy. However, factors clinically associated with NDRD in patients with NIDDM remain unclear. Therefore we reviewed clinical data, laboratory data and renal biopsies from 22 NIDDM patients who underwent renal biopsy between 1992 and 1998 in Wonju Christian Hospital. From this data, we identified important features that would discriminate between DN and NDRD. There were 8 women and 14 men. Age ranged from 33 to 68 (51.2 +/- 10.7) years. The duration of diabetes at biopsy ranged from 0 to 13 (4.2 +/- 4.2) years. Nephrotic syndrome was present in 13 patients. The patients with NDRD (n = 14) and DN (n = 8) had comparable 24-hour proteinuria, 24-hour albuminuria, creatinine clearance, serum creatinine, albumin, as well as incidences of neuropathy and hypertension. The significant factors that predict the NDRD included a short duration of the diabetes mellitus, the presence of dysmorphic red blood cells in urine, the absence of retinopathy and HbA1c below 9% (p < 0.05, respectively). NDRD included IgA nephropathy (n = 6), minimal change disease (n = 3), membranous nephropathy (n = 3), membranous lupus nephritis (n = 1) and acute interstitial nephritis (n = 1). Multiple logistic regression analysis revealed that the short duration of DM and the absence of retinopathy were factors significantly associated with NDRD. In summary, when there is a short duration of diabetes mellitus, or an absence of retinopathy seen in patients with NIDDM, then renal biopsy in diabetic patients aids in the detection of NDRD.

ATP-dependent degradation of SulA, a cell division inhibitor, by the HslVU protease in Escherichia coli

HslVU is an ATP-dependent protease consisting of two multimeric components, the HslU ATPase and the HslV peptidase. To gain an insight into the role of HslVU in regulation of cell division, the reconstituted enzyme was incubated with SulA, an inhibitor of cell division in Escherichia coli, or its fusion protein with maltose binding protein (MBP). HslVU degraded both proteins upon incubation with ATP but not with its nonhydrolyzable analog, ATPgammaS, indicating that the degradation of SulA requires ATP hydrolysis. The pulse-chase experiment using an antibody raised against MBP-SulA revealed that the stability of SulA increased in hsl mutants and further increased in lon/hsl double mutants, indicating that SulA is an in vivo substrate of HslVU as well as of protease La (Lon). These results suggest that HslVU in addition to Lon plays an important role in regulation of cell division through degradation of SulA.

The effect of tetrandrine and extracts of Centella asiatica on acute radiation dermatitis in rats

Radiation injury to the skin is one of the major limiting factors in radiotherapy. We designed this study using Sprague-Dawley rats to evaluate the reduction in skin injury achieved using natural products from plant extracts as protection. The acute skin reaction in tetrandrine- and Madecassol-treated animals appeared earlier, but was significantly less severe, than in the control group. The peak skin reactions in the tetrandrine group were less serious than those of the control group at three different radiation doses. At a high dose irradiation, the healing effect of tetrandrine is better than Madecassol and vaseline. The histologic findings indicate that tetrandrine and Madecassol are able to reduce acute radiation reactions by their anti-inflammatory activity.

Pure orbital blowout fracture: new concepts and importance of medial orbital blowout fracture

Pure orbital blowout fracture first occurs at the weakest point of the orbital wall. Although the medial orbital wall theoretically should be involved more frequently than the orbital floor, the orbital floor has been reported as the most common site of pure orbital blowout fractures. A total of 82 orbits in 76 patients with pure orbital blowout fracture were evaluated with computed tomographic scans taken on all patients with any suspicious clinical evidence, including nasal fracture. Isolated medial wall fracture was most common (55 percent), followed by medial and inferior wall fracture (27 percent). The most common facial fracture associated with medial wall fracture was nasal fracture (51 percent), not inferior wall fracture (33 percent). This finding suggests that the force causing nasal fracture is an important causative factor of pure medial wall fracture as the buckling force from the medial orbital rim. Of patients with medial wall fractures, 25 percent had diplopia and 40 percent had enophthalmos. On plain radiographs, diagnostic signs were found in 79 percent of medial wall fractures and in 95 percent of inferior wall fractures. On computed tomographic scans, late enophthalmos was expected in 76 percent of medial wall fractures. Therefore, the medial orbital blowout fracture may be an important cause of late enophthalmos, because it has a high incidence of occurrence, a low diagnostic rate, and a high severity of defect. Among the causes of limitation of ocular motility, muscle traction of the connective septa and direct muscle injury were found frequently, but true incarceration of the muscle was extremely rare in all fractures. The medial and inferior orbital walls are clearly demarcated by the bony buttress, which is an important structure supporting these orbital walls. Its buttress was closely correlated with the fracture of these orbital walls. Most orbital blowout fractures without collapse of the bony buttress had a trapdoor fracture with or without small fragments of punched-out fracture.

Explosive burns during abusive inhalation of butane gas

Explosion burns during abusive inhalation of butane gas rarely occurred in the past, but recently it has become a social problem among groups of teenagers. This cause constitutes 1.6% of admissions due to flame burn at the burn unit of Hallym Medical Center. A retrospective review during a five-year period identified 48 patients. The male to female ratio was 3:1. The mean age of patients was 16 years and 8 months. The places where the accidents occurred were commonly bedrooms or motel rooms. There were nine group settings of 27 patients at the time of the accident. Inhalation injury (n = 12) was noted on admission. The average burn size was 28.5 percent of the total body surface area. All patients sustained burn injury on the face, arms and hands and 24 patients among them had extended burn areas on the trunk and/or lower extremity. 22 patients (mean hospital stay; 51.6 d) required skin grafting and 12 patients (mean hospital stay; 22.3 d) were treated with conservative management. The mortality rate was 10.4 percent. Explosion burns during abusive inhalation of butane gas can result in mortality as well as major burn injuries.

Neuregulin stimulates myogenic differentiation in an autocrine manner

During myogenesis, mononucleated myoblasts form multinucleated myotubes by membrane fusion. Efficiency of this intercellular process can be maximized by a simultaneous progress, with a time window, of other neighboring myoblasts in the differentiation program. This phenomenon has been described as the community effect. It proposes the existence of a molecule that acts as a differentiation-inducing signal to a group of identical cells. Here, we show that neuregulin is a strong candidate for this molecule in myoblast differentiation. The expression of neuregulin increased rapidly but transiently at early stage of differentiation of rat L6 cells. Neuregulin showed a potent differentiation-promoting activity in membrane fusion and expression of myosin heavy chain. The antibodies raised against neuregulin and its cognate receptor ErbB3, which were capable of neutralizing the signal pathway, inhibited myotube formation and expression of myosin heavy chain in both L6 cells and primary rat myoblasts. The progress of differentiation was mostly halted after the expression of myogenin and cell cycle arrest. These results suggest that the activation of an autocrine signaling of neuregulin may provide a basic mechanism for the community effect observed in the differentiation of the embryonic muscle cells.

Crystallization and preliminary X-ray crystallographic analysis of the protease inhibitor ecotin in complex with chymotrypsin

Ecotin, a homodimeric protein composed of 142-residue subunits, is a novel protease inhibitor present in the periplasm of Escherichia coli. It shows a broad inhibitory specificity towards a group of serine proteases and binds two molecules of protease to form a tetrameric complex in a distinct chelation mechanism. The ecotin-chymotrypsin complex has been crystallized in the triclinic space group P1 with unit-cell parameters a = 57.29, b = 57.39, c = 79.75 A, alpha = 91.49, beta = 88.63 and gamma = 112.45 degrees. The asymmetric unit contains the whole tetrameric complex, consisting of two molecules of chymotrypsin bound to the ecotin dimer, with a corresponding crystal volume per protein mass (VM) of 2.58 A3 Da-1 and a solvent fraction of 48.9%. The crystals diffract beyond 2.0 A with Cu Kalpha X-rays and are very stable in the X-ray beam. Native X-ray data have been collected from a crystal to approximately 2.0 A Bragg spacing.

Shear bond strengths of two resin-modified glass ionomer cements to porcelain

Shear bond strength of a composite resin adhesive (Concise) and two resin-modified glass ionomer cements (Fuji Ortho LC and Geristore) bonded to porcelain surface was tested. Orthodontic brackets were bonded to 120 porcelain disks (Finesse) etched with 9% HF. Samples were divided into six groups: (1) Concise, (2) Concise/silane, (3) Geristore, (4) Geristore/silane, (5) Fuji, (6) Fuji/silane. No statistical difference in mean shear bond strength was found between silanated Concise (15.8 MPa), Geristore (19.4 MPa), and Fuji (18.5 MPa) groups, which were significantly higher than nonsilanated groups. Porcelain fracture was observed in all silanated groups and nonsilanated Geristore group. We conclude that (1) silane increases bond strength to porcelain significantly for composite resin and resin-modified glass ionomer cement, (2) Concise, Geristore, and Fuji Ortho LC provide comparable shear bond strength to porcelain.

Receptor activator of NF-kappaB recruits multiple TRAF family adaptors and activates c-Jun N-terminal kinase

Receptor activator of NF-kappaB (RANK) is a recently cloned member of the tumor necrosis factor receptor (TNFR) superfamily, and its function has been implicated in osteoclast differentiation and dendritic cell survival. Many of the TNFR family receptors recruit various members of the TNF receptor-associated factor (TRAF) family for transduction of their signals to NF-kappaB and c-Jun N-terminal kinase. In this study, the involvement of TRAF family members and the activation of the JNK pathway in signal transduction by RANK were investigated. TRAF1, 2, 3, 5, and 6 were found to bind RANK in vitro. Association of RANK with each of these TRAF proteins was also detected in vivo. Expression of RANK in cultured cells also induced the activation of JNK, which was blocked by a dominant-negative form of JNK. Furthermore, by employing various C-terminal deletion mutants of RANK, the regions responsible for TRAF interaction and JNK activation were identified. TRAF5 was determined to bind to the C-terminal 11 amino acids and the other TRAF members to a region N-terminal to the TRAF5 binding site. The domain responsible for JNK activation was localized to the same region where TRAF1, 2, 3, and 6 bound, which suggests that these TRAF molecules might mediate the RANK-induced JNK activation.

Shear bond strength of a resin-reinforced glass ionomer cement: an in vitro comparative study

Shear bond strength of Concise (a composite resin adhesive) and Fuji Ortho LC (a light-cured resin-reinforced glass ionomer cement) bonded to extracted teeth was tested under different bonding conditions: (1) Concise/etched/dry (2) Fuji/etched/dry (3) Fuji/etched/wet (4) Fuji/unetched/dry (5) Fuji/unetched/wet. Concise/etched/dry and Fuji/etched/dry groups showed comparable mean shear bond strength (10.5 and 8.2 MPa, respectively); the other three groups had considerably lower values. The difference between Fuji/etched/dry and Fuji/etched/wet was not statistically significant. The site of bond failure was between bracket and adhesive in all etched groups and between adhesive and enamel in the unetched groups. We conclude that (1) enamel surface etching is required for Fuji Ortho LC to achieve optimum bond strength, (2) moisture does not affect bond strength of Fuji Ortho LC significantly.

Cloning and characterization of a seed-specific omega-3 fatty acid desaturase cDNA from Perilla frutescens

A cDNA encoding omega-3 fatty acid desaturase was isolated from developing perilla seeds and characterized. On the basis of its deduced amino acid sequence comparison, this cDNA was assumed to be a new isoform of microsomal omega-3 fatty acid desaturase gene. Accumulation of the mRNA for this cDNA showed seed-specific expression.

Identification and chromosomal assignment of USP1, a novel gene encoding a human ubiquitin-specific protease

We have cloned a novel gene encoding a human ubiquitin-specific protease (USP1). The product, which consists of 785 amino acids with a deduced molecular mass of 88.2 kDa, possesses His and Cys domains that are highly conserved in all members of the ubiquitin-specific processing (UBP) family of proteases. Recombinant USP1 protein showed genuine UBP activity, correctly cleaving Ub-beta-galactosidase to produce ubiquitin and beta-galactosidase. Chromosomal mapping by fluorescence in situ hybridization and radiation hybrid analyses localized the USP1 gene to the p31.3-p32.1 band of chromosome 1. As losses of heterozygosity or amplifications have been observed in the distal region of the short arm of chromosome 1 in some neuroblastomas, breast cancers, and pancreatic adenocarcinomas, the USP1 gene may be a candidate for either the tumor-suppressive or the oncogenic activities associated with that chromosomal region.

Calculus-like deposit at apex of tooth with refractory apical periodontitis

It is generally accepted that bacteria in or outside the root canal are the reason for apical periodontitis and endodontic failures. This case report presents a 60-year-old woman with a periapical lesion and a fistulous tract which did not respond to conventional root canal treatment. During periapical surgery, granulomatous tissue was removed and a calculus-like deposit was observed on the root surface. A radicular cyst was diagnosed. Nine months after this calculus-like deposit had been removed and the cyst enucleated, complete recovery of the bone had occurred. It is suggested that the presence of the calculus-like deposit at the apex of the tooth or its effects may in part have delayed the healing of the periapical inflammation in spite of apparently adequate endodontic treatment.

A novel family of ubiquitin-specific proteases in chick skeletal muscle with distinct N- and C-terminal extensions

We have recently identified a cDNA for a ubiquitin-specific protease (UBP), UBP41, that encodes the smallest functional UBP identified to date, using an Escherichia coli-based in vivo screening method. In the present study we isolated highly related cDNAs encoding a new family of UBP enzymes, named UBP46, UBP52 and UBP66. These UBPs have virtually identical catalytic domains spanning the sequence of UBP41 between the active-site Cys and the His box (95% identity). However, they possess distinct N- and/or C-terminal extensions. Moreover, they are more closely related to each other than to any other members of the UBP family. Thus these chick UBPs must define a novel family of de-ubiquitinating enzymes and should represent the first example among the UBP family enzymes, whose multiplicity is achieved by variation in their N- and C-terminal extensions. The chick UBPs were expressed in E. coli, and purified from the cells to apparent homogeneity using 125I-labelled ubiquitin-alphaNH-MHISPPEPESEEEEEHYC as a substrate. Each of the purified UBP46, UBP52 and UBP66 enzymes behaved as proteins of similar sizes under both denaturing and non-denaturing conditions, suggesting that all of them consist of a single polypeptide chain. The UBP enzymes cleaved the C-terminus of the ubiquitin moiety in natural and engineered fusions irrespective of their sizes and thus are active against ubiquitin-beta-galactosidase as well as a ubiquitin C-terminal extension protein of 80 amino acids. All UBPs except UBP66 released free ubiquitin from poly-His-tagged di-ubiquitin. However, the isopeptidase activity for hydrolysing polyubiquitinated lysozyme conjugates was not detected from these UBPs, which makes these UBPs distinct from UBP41. These results suggest that the chick UBPs may play an important role in production of free ubiquitin from linear polyubiquitin chains and of certain ribosomal proteins from ubiquitin fusion proteins.

LonR9 carrying a single Glu614 to Lys mutation inhibits the ATP-dependent protease La (Lon) by forming mixed oligomeric complexes

An unusual lon mutation (called lonR9) is dominant over the wild-type gene, which encodes the ATP-dependent protease La (Lon) in Escherichia coli, when present in multicopy plasmids. Here, we cloned and sequenced lonR9, and showed that the mutant gene carries a single point mutation in its open reading frame, which leads to replacement of Glu614 by Lys. The LonR9 protein and its poly-His-tagged form were purified to apparent homogeneity. Both of the purified proteins were capable of inhibiting the ATP-dependent proteolysis and the protein-activated ATP hydrolysis by protease La. Furthermore, the His-tagged LonR9 protein was found to form mixed oligomeric complexes with protease La, upon analysis by chromatography on a metal-chelating column. These results suggest that the phenotypic dominance of the lonR9 mutant is due to the formation of mixed oligomeric complexes between LonR9 and protease La, in which the defective components prevent the function of the wild-type subunits.

Effects of the cys mutations on structure and function of the ATP-dependent HslVU protease in Escherichia coli. The Cys287 to Val mutation in HslU uncouples the ATP-dependent proteolysis by HslvU from ATP hydrolysis

To define the role of the Cys residues in the ATP-dependent HslVU protease, mutagenesis was performed to replace either Cys261 or Cys287 in HslU with Val and Cys159 in HslV with Ser or Ala. Whereas HslU/C261V could hydrolyze ATP and support the ATP-dependent proteolytic activity of HslV as well as the wild-type HslU, HslU/C287V could not hydrolyze ATP. Nevertheless, HslU/C287V could support the HslV-mediated proteolysis by forming the HslVU complex in the presence of ATP but not its absence, indicating that ATP binding but not its hydrolysis is essential for proteolysis. Whereas treatment of N-ethylmaleimide (NEM) resulted in dissociation of the oligomeric HslU into monomers, the C261V mutation, but not C287V, prevented the NEM effect. These results suggest that Cys261 is involved in oligomerization and that Cys287 is related to the ATPase function of HslU. NEM also dissociated the dodecameric HslV into monomers, and this effect could be prevented by either the C159S or C159A mutation, suggesting the involvement of Cys159 in oligomerization of HslV. Moreover, either mutation abolished both the basal and HslU-activated proteolytic activity of HslV and its ability to activate the HslU ATPase and to form the HslVU complex, indicating that Cys159 is essential for the proteolytic activity of HslV and its interaction with HslU. These results suggest that the Cys residues play an important role in maintaining the structure and function of the HslVU protease.

Inhibitors of the proteasome block the myogenic differentiation of rat L6 myoblasts

Myogenesis is characterized by membrane fusion and accumulation of muscle specific proteins. We have previously shown that nitric oxide acts as a messenger for membrane fusion. Here we show that inhibitors of the proteasome, such as lactacystin, reversibly block both the fusion of L6 myoblasts and the accumulation of muscle specific proteins, such as myosin heavy chain (MHC). The inhibitors also reversibly prevented the induction of the NF-kappaB activity, which is required for the expression of nitric oxide synthase (NOS). Moreover, the inhibition of the NF-kappaB activity occurred in parallel with that of the NOS activity upon treatment with increasing concentrations of lactacystin. While pyrrolidine dithiocarbamate, an inhibitor of NF-kappaB, blocked both membrane fusion and accumulation of MHC, N(G)-monomethyl-L-arginine, a specific inhibitor of NOS, inhibited only the fusion. These results suggest that the proteasome plays an essential role in the regulation of myogenic differentiation through the activation of NF-kappaB and that the target of NF-kappaB for the expression of muscle specific proteins is distinct from that for myoblast fusion.

Mutational analysis of the two ATP-binding sites in ClpB, a heat shock protein with protein-activated ATPase activity in Escherichia coli

The 93 kDa ClpB (ClpB93) is a heat shock protein and has a protein-activated ATPase activity. To define the role of the two ATP-binding sites in ClpB93, site-directed mutagenesis was performed to replace Lys212 or Lys611 with Thr or Glu. All of the mutant proteins hydrolysed ATP at a higher rate than that seen with ClpB93 at ATP concentrations up to 2 mM. However, ClpB93 carrying mutations in both of the ATP-binding sites could not cleave ATP. Thus any of the two ATP-binding sites seems to be capable of supporting the ATPase activity of ClpB93. The ATPase activities of both ClpB93/K212T and ClpB93/K212E were gradually decreased when ATP concentrations were increased above 2 mM, unlike those of ClpB93, ClpB93/K611T and ClpB93/K611E, which showed a typical saturation curve. Furthermore ADP inhibited ATP hydrolysis by ClpB93/K212T and ClpB93/K212E more effectively than that by the latter proteins, suggesting that the mutations in the first ATP-binding site result in an increase in the affinity of ADP for the second site in ClpB93. In addition, all of the purified ClpB93 and its mutant forms behaved as an oligomer of 400-450 kDa on a Sephacryl S-300 gel-filtration column, whether or not ATP was present. Thus the binding of ATP to either of the two sites seems not to be essential for oligomerization of ClpB93. Although a low-copy plasmid carrying clpB93 could rescue the sensitivity of a clpB-null mutant cell at 52 degreesC, none of the plasmids carrying the mutations in the ATP-binding sites could. Furthermore, incubation at 52 degreesC resulted in a gradual loss of the ATPase activity of ClpB93 carrying the mutations in either of the two ATP-binding sites, but not of the parental ClpB93, indicating that the mutant proteins have a greater tendency to denature at this temperature than the parental ClpB93. These results suggest that both of the ATP-binding sites in ClpB have an important role in maintaining the thermotolerance of the protein and hence in the survival of Escherichia coli at high temperatures.

cDNA cloning and characterization of a human proteasomal modulator subunit, p27 (PSMD9)

We have employed cDNA cloning to deduce the complete primary structure of a new subunit, designated p27, of the modulator trimer complex that stimulates the association of the PA700 regulator with the catalytic 20S proteasome to form the ATP-dependent active 26S proteasome. We found two distinct cDNAs encoding two highly homologous proteins except in the C-terminal region, which are termed tentatively p27-1 and p27-2. The short p27-2 cDNA has a deletion of 65 bp near the 3'-end region of the long p27-1 cDNA, which encodes a large protein with an extended C-terminal region, designated p27-L, whereas the long p27-1 cDNA encodes a small protein named p27-S. The polypeptides of p27-L and p27-S consist of 223 and 209 amino acid residues with calculated molecular masses of 24,852 and 22,764 and isoelectric points of 6.50 and 5.28, respectively. Immunoblot analysis with anti-p27 antibody revealed that p27, together with two other ATPase components, TBP1 and p42, was associated with not only the modulator complex but also significantly with the 26S proteasome complex, suggesting that the three are common/sharing subunits in these two complexes. By the fluorescence in situ hybridization method, the p27 (PSMD9) gene was mapped to the q24.2-q24.3 band of human chromosome 12. Computer-assisted homology analysis revealed the high sequence similarities of p27-L with a possible counterpart in Caenorhabditis elegans and Saccharomyces cerevisiae whose function is yet unknown, the yeast gene that is here termed NAS2 (non-ATPase subunit 2). Disruption of NAS2 had no effect on cell viability, indicating that the subunit is not essential for proliferation of yeast cells.

Chromosomal localization and immunological analysis of a family of human 26S proteasomal ATPases

The 26S proteasome is a eukaryotic ATP-dependent protease functioning as a protein death machine. It is a large multisubunit complex, consisting of a catalytic 20S proteasome and two regulatory modules, named PA700. The PA700 complex is composed of multiple subunits of 25-110 kDa, which are classified into two subgroups, a subgroup of at least 6 ATPases that consitute a unique multi-gene family encoding homologous polypeptides conserved during evolution and a subgroup of approximately 15 non-ATPase subunits, most of which are structurally unrelated to each other. In the present study, we report the chromosomal localization and immunological properties of six members of the human 26S proteasomal ATPase family. By use of the fluorescence in situ hybridization method, the S4 (PSMC1), MSS1 (PSMC2), TBP1 (PSMC3), TBP7 (PSMC4), p45 (PSMC5), and p42 (PSMC6) genes were mapped to human chromosomes 19p13.3, 7q22.1-q22.3, 11p11.2, 19q13.11-q13.13, 17q23.1-q23.3, and 12q15, respectively, indicating that the genes for multiple ATPases of the 26S proteasome are located on different chromosomes. Immunoblot analysis revealed that all these ATPases were associated with the purified 26S proteasome and that some of them showed striking heterogeneity in their electrical charges.

K-ras mutations in the duodenal fluid of patients with pancreatic carcinoma

BACKGROUND

Many patients with carcinoma of the pancreas die because their disease is not detected until late in its course. Methods that detect these cancers earlier will improve patient outcome. Over 80% of pancreatic carcinomas contain mutations in codon 12 of the K-ras gene. Screening duodenal fluid for these mutations may lead to early detection of these cancers and assist in establishing a diagnosis of pancreatic carcinoma.

METHODS

Polymerase chain reaction (PCR), with and without restriction enzyme-mediated mutant enrichment, was performed on DNA isolated from duodenal fluid specimens from 61 patients who underwent pancreaticoduodenectomy (Whipple's operation) for either periampullary cancer or a benign condition of the pancreas. Representative sections of pancreas pathology (primary carcinoma, benign tumor, or chronic pancreatitis) from the patients with duodenal fluid specimens containing amplifiable DNA were also analyzed for K-ras mutations. Wild-type and mutant K-ras were detected by hybridization of the PCR products with K-ras codon 12 mutant and wild-type specific probes.

RESULTS

Seven of the 61 duodenal fluid specimens contained DNA that did not amplify. Thirteen (24% of the 54 duodenal fluid specimens with amplifiable DNA and 21% of the total of 61 specimens) contained activating point mutations at codon 12 of the K-ras gene. Mutations were detected in 13 of the 51 duodenal fluid specimens from patients with cancer (sensitivity, 25%), whereas mutations were not detected in any of the 9 amplifiable duodenal fluid specimens from patients with benign conditions of the pancreas (specificity, 100%). One duodenal fluid specimen from a patient with adenocarcinoma of the pancreas had two different K-ras mutations. DNA from three of the primary carcinomas did not amplify or was not available. Twenty-nine (69%) of the 42 primary tumors with amplifiable DNA contained K-ras mutations, whereas 3 (30%) of the 10 pancreata with benign conditions harbored mutations. Twenty-two (65%) of 34 ductal adenocarcinomas of the pancreas with amplifiable DNA had K-ras mutations. It is noteworthy that the same mutation was present in both the duodenal fluid and the primary carcinomas of 11 (92%) of the 12 patients who had primary tumors with amplifiable DNA as well as K-ras mutations in their duodenal fluid specimens.

CONCLUSIONS

The identification of genetic alterations in cancer-causing genes in duodenal fluid may form the basis for the development of new approaches to the detection of carcinoma of the pancreas. Some pancreata without cancer, however, may also harbor K-ras mutations, potentially limiting the specificity of K-ras-based tests.

Induction of apoptosis in human leukemic U937 cells by tetrandrine

Tetrandrine, a calcium channel antagonist, is a plant alkaloid possessing various pharmacological activities including anti-tumor activity. We studied tetrandrine to determine whether or not this anti-tumor effect occurs through induction of apoptosis. Tetrandrine inhibited both proliferation and clonogenicity of human leukemic U937 cells at an optimal concentration of 2.5 microg/ml. This growth inhibition was dose and time dependent, and accompanied with evidence of apoptotic changes. The characteristic morphological changes of apoptosis were observed in U937 cells under light microscopy and DNA fragmentation was noted by gel electrophoresis. Moreover, flow cytometric detection of surface phosphatidyl serine expression of U937 cells after treatment with tetrandrine confirmed the induction of apoptosis in these cells. The induction of apoptosis by tetrandrine would appear to proceed via non-Ca2+-dependent pathways.

K-ras mutations in the duodenal fluid of patients with pancreatic carcinoma

BACKGROUND

Many patients with carcinoma of the pancreas die because their disease is not detected until late in its course. Methods that detect these cancers earlier will improve patient outcome. Over 80% of pancreatic carcinomas contain mutations in codon 12 of the K-ras gene. Screening duodenal fluid for these mutations may lead to early detection of these cancers and assist in establishing a diagnosis of pancreatic carcinoma.

METHODS

Polymerase chain reaction (PCR), with and without restriction enzyme-mediated mutant enrichment, was performed on DNA isolated from duodenal fluid specimens from 61 patients who underwent pancreaticoduodenectomy (Whipple's operation) for either periampullary cancer or a benign condition of the pancreas. Representative sections of pancreas pathology (primary carcinoma, benign tumor, or chronic pancreatitis) from the patients with duodenal fluid specimens containing amplifiable DNA were also analyzed for K-ras mutations. Wild-type and mutant K-ras were detected by hybridization of the PCR products with K-ras codon 12 mutant and wild-type specific probes.

RESULTS

Seven of the 61 duodenal fluid specimens contained DNA that did not amplify. Thirteen (24% of the 54 duodenal fluid specimens with amplifiable DNA and 21% of the total of 61 specimens) contained activating point mutations at codon 12 of the K-ras gene. Mutations were detected in 13 of the 51 duodenal fluid specimens from patients with cancer (sensitivity, 25%), whereas mutations were not detected in any of the 9 amplifiable duodenal fluid specimens from patients with benign conditions of the pancreas (specificity, 100%). One duodenal fluid specimen from a patient with adenocarcinoma of the pancreas had two different K-ras mutations. DNA from three of the primary carcinomas did not amplify or was not available. Twenty-nine (69%) of the 42 primary tumors with amplifiable DNA contained K-ras mutations, whereas 3 (30%) of the 10 pancreata with benign conditions harbored mutations. Twenty-two (65%) of 34 ductal adenocarcinomas of the pancreas with amplifiable DNA had K-ras mutations. It is noteworthy that the same mutation was present in both the duodenal fluid and the primary carcinomas of 11 (92%) of the 12 patients who had primary tumors with amplifiable DNA as well as K-ras mutations in their duodenal fluid specimens.

CONCLUSIONS

The identification of genetic alterations in cancer-causing genes in duodenal fluid may form the basis for the development of new approaches to the detection of carcinoma of the pancreas. Some pancreata without cancer, however, may also harbor K-ras mutations, potentially limiting the specificity of K-ras-based tests.