The role of bacteria in gallstone pathogenesis

Bacteria are often found in high concentrations in brown pigment and less so in cholesterol gallstones. Although it is intriguing to hypothesize that cholesterol stone formation is non-bacterial in nature and principally different from the pathogenesis of "infectious" brown pigment gallstones, it is more likely that significant overlap exists between the two processes. Most gallstones are composite in nature. Using molecular-genetic methods, bacteria can be found in most pure cholesterol gallstones (i.e. those whose structure consists of more than 90% cholesterol). The natural history of the gallstones development is unknown. It is likely that brown pigment stones can evolve in their chemical composition after the termination of the infectious process that initiate their formation, and may further develop into either mixed or nearly pure cholesterol stones. In a similar fashion, cholesterol-poor or black pigment gallstones may act as foreign bodies to enhance the propensity of bacterial colonization in the presence of pre-existing gallstones or cholangitis, thereby activating pathways of bacterial lithogenesis and resulting in the encasement of cholesterol nuclei with pigment shells and/or in the internal remodeling of extant stones. It is often difficult, if not impossible, to ascertain whether bacterial infection of bile arose before stone formation or vice-versa. The development of gallstones (nucleation, assembly of microcalculi, growth, remodeling) includes the interaction of both bacterial and non-bacterial mechanisms, working discontinuously over years and decades and shaping the structural individuality of each stone. At cholecystectomy, the gallstone removed from the patient represents the end product of a long pathologic process. Although our understanding of the exact temporal contribution of bacteria in lithogenesis is incomplete, it is important for the clinician to realize that most gallstones are colonized by a bacterial biofilm, even though the bile may be culture-negative.

Variations of the prominences of the bony palate and their relationship to complete dentures in Korean skulls

The osteological and morphological variations of the prominences in the bony palate of 160 Korean skulls were studied. The frequency of the occurrence of the posterior palatine crest, located on the posterior border of the greater palatine foramen, was 13.8%. Palatal ridges were observed commonly in the skulls; however, the smooth type, which has no palatal ridges in the palate, was shown in 14.7% of cases, and palatal spines were observed in 33.8%. The prevalence of palatal tubercles was 11.6%, and all were found in the molar region. The palatine torus was found in 18.8% of cases and the most common type was along the median palatine suture from the incisive foramen to the posterior border of the palatine bone (63.3%). No significant differences between sexes or sides were found in the posterior palatine crest, palatal ridges, and palatal tubercle. However, the sex distribution of the palatine torus was significantly different (P < 0.05). These results would be helpful clinically in fabricating maxillary complete dentures for edentulous patients.

Gallstones

Gallstones are estimated to affect over 20 million people in the United States. Recent studies have clarified the role of various dietary components in gallstone disease. Also, insulin resistance has been demonstrated to be a risk factor for gallstones. Other research has focused on the pathophysiology of gallstones and on clarifying the underlying mechanisms of previously noted risk factors for gallstones. New techniques for the noninvasive diagnosis of bile duct stones continue to be developed and tested. These techniques include computed tomography and magnetic resonance cholangiography. The impact and appropriateness of laparoscopic cholecystectomy continue to debated, and studies point to both overuse and underuse of this operation in the management of the disease.

Epstein-Barr virus-specific cytotoxic T lymphocyte responses in the blood and tumor site of Hodgkin's disease patients: implications for a T-cell-based therapy

Approximately 40% of Hodgkin's disease (HD) cases carry EBV in the malignant Hodgkin-Reed Sternberg (H-RS) cells, with expression of viral latent membrane proteins (LMPs) 1 and 2. These viral proteins are targets for CTLs in healthy EBV carriers, and their expression in EBV-associated HD raises the possibility of targeting them for a CTL-based immunotherapy. Here we characterize the CTL response to EBV latent antigens in both the blood and tumor-infiltrating lymphocytes of HD patients using two approaches: (a) in vitro reactivation of CTLs by stimulation with the autologous EBV-transformed lymphoblastoid cell line; and (b) an enzyme-linked immunospot assay to quantify frequencies of CTLs specific for known LMP1/2 epitopes. We detected EBV-specific CTLs in blood and biopsy samples from both EBV-negative and EBV-positive HD patients. However, as in healthy EBV carriers, LMP-specific CTL precursors occurred only at low frequency in the blood of HD patients, and with the exception of one EBV-negative HD case, were undetectable in the tumor. These data give rise to two considerations: (a) they may explain why EBV-positive tumor cells persist in the presence of an existing EBV-specific immune response; and (b) they provide a rationale for selectively boosting/eliciting LMP-specific CTL responses as a therapy for EBV-positive HD.

Cyclophilin a binds to peroxiredoxins and activates its peroxidase activity

Six distinct peroxiredoxin (Prx) proteins (Prx I-VI) from distinct genes have been identified in mammalian tissues. Prxs are members of a group of peroxidases that have conserved reactive cysteine residue(s) in the active site(s). An immediate physiological electron donor for the peroxidase catalysis for five Prx proteins (Prx I-V) has been identified as thioredoxin (Trx), but that for Prx VI (1-Cys Prx) is still unclear. To identify an immediate electron donor and a binding protein for Prx VI, we performed a Prx VI protein overlay assay. A 20-kDa binding protein was identified by the Prx VI protein overlay assay with flow-through fractions from a High-Q column with rat lung crude extracts. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and MS-Fit, we identified the 20-kDa Prx VI-binding protein as a cyclophilin A (CyP-A). The binding of recombinant human CyP-A (hCyP-A) to Prx VI was confirmed by using the hCyP-A protein overlay assay and Western immunoblot analysis with hCyP-A-specific antibodies. hCyP-A enhanced the antioxidant activity of Prx VI, as well as the other known mammalian Prx isotypes. hCyP-A supported antioxidant activity of Prx II and Prx VI both against thiol (dithiothreitol)-containing metal-catalyzed oxidation (MCO) systems and ascorbate-containing MCO systems. Prx II was reduced by hCyP-A without help from any other reductant, and the reduction was cyclosporin A-independent. These results strongly suggest that CyP-A not only binds to Prx proteins but also supports its peroxidase activity as an immediate electron donor. In addition, Cys(115) and Cys(161) of hCyP-A were found to be involved in the activation and the reduction of Prx.

The effect of total sleep deprivation on cognitive functions in normal adult male subjects

This study was conducted to evaluate the effect of acute sleep deprivation on cognitive functions. A total of 18 healthy right handed males were deprived of sleep for 24 hours. Luria-Nebraska Neuropsychological Battery and calculation & digit-span subtest of K-WAIS were administered before and after sleep deprivation in order to examine the changes of cognitive functions. There were no differences in freedom from distractibility, tacile function, visual function, reading, writing, arithmetic and intellectual process function. However, the cognitive functions such as motor, rhythm, receptive & expressive speech, memory and complex verbal arithmetic function were decreased after sleep deprivation. All of these functions are known to be related to the right anterior hemisphere. For localization scales, the scores of right frontal and right temporal dysfunction scale were increased after sleep deprivation. These results indicate that sleep deprivation has a negative effect on cognitive functions, especially those associated with right anterior hemisphere or subcortical areas.

Identification of oxysterols in human bile and pigment gallstones

BACKGROUND AND AIMS

Although cholesterol is the most abundant sterol in animal tissues, oxidized products of cholesterol (oxysterols) also occur in mammalian organs and blood and are cytotoxic, atherogenic, and carcinogenic. However, the presence of oxysterols in bile or gallstones has never been reported.

METHODS

Fresh human bile and gallstones were collected. Sterol content and structure were analyzed using gas chromatography/mass spectrometry (GC/MS). Bacterial DNA was extracted from human gallstones.

RESULTS

GC/MS identified cholesta-4,6-diene-3-one and cholest-4-ene-3-one, with several as yet unidentified oxysterols in bile and stone samples. Several plant and fungal sterols were also present in gallstones. When 102 human gallstones were analyzed for oxysterols, they were markedly higher (as percent of total sterols) in pigment gallstones, where bacterial DNA is most abundant.

CONCLUSIONS

These observations suggest biliary oxysterols are associated with the presence of bacteria and may play a role in the pathogenesis of gallstones and biliary tract cancers.

In vivo measurements of brain glucose transport using the reversible Michaelis-Menten model and simultaneous measurements of cerebral blood flow changes during hypoglycemia

Glucose is the major substrate that sustains normal brain function. When the brain glucose concentration approaches zero, glucose transport across the blood-brain barrier becomes rate limiting for metabolism during, for example, increased metabolic activity and hypoglycemia. Steady-state brain glucose concentrations in alpha-chloralose anesthetized rats were measured noninvasively as a function of plasma glucose. The relation between brain and plasma glucose was linear at 4.5 to 30 mmol/L plasma glucose, which is consistent with the reversible Michaelis-Menten model. When the model was fitted to the brain glucose measurements, the apparent Michaelis-Menten constant, Kt, was 3.3 +/- 1.0 mmol/L, and the ratio of the maximal transport rate relative to CMRglc, Tmax/CMRglc, was 2.7 +/- 0.1. This Kt is comparable to the authors' previous human data, suggesting that glucose transport kinetics in humans and rats are similar. Cerebral blood flow (CBF) was simultaneously assessed and constant above 2 mmol/L plasma glucose at 73 +/- 6 mL 100 g(-1) min(-1). Extrapolation of the reversible Michaelis-Menten model to hypoglycemia correctly predicted the plasma glucose concentration (2.1 +/- 0.6 mmol/L) at which brain glucose concentrations approached zero. At this point, CBF increased sharply by 57% +/- 22%, suggesting that brain glucose concentration is the signal that triggers defense mechanisms aimed at improving glucose delivery to the brain during hypoglycemia.

Characterization of model bile using fluorescence energy transfer from dehydroergosterol to dansylated lecithin

Fluorescence energy transfer from dehydroergosterol (DHE) to dansylated lecithin (DL) was used to characterize lecithin-cholesterol vesicles in the presence of the bile salt, sodium taurocholate. At lipid concentrations approximating physiological levels, exposure of fluorescently labeled vesicles to the bile salt led to a dose-dependent increase in the DHE-to-DL fluorescence ratio during the first 24 h after mixing. The initial changes in the fluorescence ratio correlated well with conventional turbidity measurements that quantify partial micellization of vesicles as a function of bile salt loading. In addition, fluorescence energy transfer from DHE to DL revealed cholesterol enrichment of vesicles and re-vesiculation of micelles at bile salt loadings for which vesicles and micelles coexisted. Samples containing the cholesterol-enriched vesicle fraction exhibited further increases in the DHE-to-DL fluorescence ratio during a 4-week observation period but only after a significant lag period of several days. The lag period decreased with cholesterol loading, and the increase in the fluorescence ratio always preceded the appearance of microscopic, birefringent, either needlelike or platelike, cholesterol crystals, in samples that were initially supersaturated with cholesterol. Cholesterol crystals were not observed, and the fluorescence ratio did not increase, for any sample that was undersaturated with cholesterol.Taken together, these results suggest that the latter changes in fluorescence are the result of cholesterol nucleation. Fluorescence energy transfer from DHE to DL is therefore a promising technique for the characterization of model bile and, possibly, provides a direct measurement of cholesterol nucleation.

Hepatic toxicity and recovery of Fischer 344 rats following exposure to 2-aminoanthracene by intraperitoneal injection

Humans may be exposed to 2-aminoanthracene (2-AA), a substituted polycyclic aromatic hydrocarbon, and a recognized mutagen and carcinogen, through oral and respiratory routes from contact with a variety of environmental sources. For the present study, we sought to evaluate hepatic damage and recovery in Fischer 344 rats following multiple i.p. injections of 5 mg of 2-AA. Rats were injected weekly for up to 5 weeks. Subgroups were then allowed to recover for 1, 5, or 9 weeks, and biochemical and pathologic changes were evaluated. We observed that weight gains were reduced relative to controls for all groups receiving > or = 2 injections. Serum enzyme levels indicative of liver damage were evident and included alterations in serum aspartate aminotransferase, alkaline phosphatase, total protein, albumin, and globulin. These alterations usually returned to normal by 5 weeks following cessation of 2-AA administration. In contrast, histologic liver changes, including hepatocyte hypertrophy, biliary hyperplasia with oval cell proliferation, altered foci, nodular hyperplasia, and one hepatocellular adenoma became more severe with time. This experiment demonstrates patterns of hepatic damage and recovery in rats exposed to 2-AA.

Relative changes of cerebral arterial and venous blood volumes during increased cerebral blood flow: implications for BOLD fMRI

Measurement of cerebral arterial and venous blood volumes during increased cerebral blood flow can provide important information regarding hemodynamic regulation under normal, pathological, and neuronally active conditions. In particular, the change in venous blood volume induced by neural activity is one critical component of the blood oxygenation level-dependent (BOLD) signal because BOLD contrast is dependent only on venous blood, not arterial blood. Thus, relative venous and arterial blood volume (rCBV) and cerebral blood flow (rCBF) in alpha-chlorolase-anesthetized rats under hypercapnia were measured by novel diffusion-weighted (19)F NMR following an i.v. administration of intravascular tracer, perfluorocarbons, and continuous arterial spin labeling methods, respectively. The relationship between rCBF and total rCBV during hypercapnia was rCBV(total) = rCBF(0.40), which is consistent with previous PET measurement in monkeys. This relationship can be linearized in a CBF range of 50-130 ml/100 g/min as DeltarCBV(total)/ DeltarCBF = 0.31 where DeltarCBV and DeltarCBF represent rCBV and rCBF changes. The average arterial volume fraction was 0.25 at a basal condition with CBF of approximately 60 ml/100 g/min and increased up to 0.4 during hypercapnia. The change in venous rCBV was 2-fold smaller than that of total rCBV (DeltarCBV(vein)/DeltarCBF = 0.15), while the arterial rCBV change was 2.5 times larger than that of total rCBV (DeltarCBV(artery)/DeltarCBF = 0.79). These NMR results were confirmed by vessel diameter measurements with in vivo videomicroscopy. The absolute venous blood volume change contributes up to 36% of the total blood volume change during hypercapnia. Our findings provide a quantitative physiological model of BOLD contrast.

Targeting antigen in mature dendritic cells for simultaneous stimulation of CD4+ and CD8+ T cells

Due to their potent immunostimulatory capacity, dendritic cells (DC) have become the centerpiece of many vaccine regimens. Immature DC (DCimm) capture, process, and present Ags to CD4(+) lymphocytes, which reciprocally activate DCimm through CD40, and the resulting mature DC (DCmat) loose phagocytic capacity, but acquire the ability to efficiently stimulate CD8(+) lymphocytes. Recombinant vaccinia viruses (rVV) provide a rapid, easy, and efficient method to introduce Ags into DC, but we observed that rVV infection of DCimm results in blockade of DC maturation in response to all activation signals, including CD40L, monocyte-conditioned medium, LPS, TNF-alpha, and poly(I:C), and failure to induce a CD8(+) response. By contrast, DCmat can be infected with rVV and induce a CD8(+) response, but, having lost phagocytic activity, fail to process the Ag via the exogenous class II pathway. To overcome these limitations, we used the CMV protein pp65 as a model Ag and designed a gene containing the lysosomal-associated membrane protein 1 targeting sequence (Sig-pp65-LAMP1) to target pp65 to the class II compartment. DCmat infected with rVV-Sig-pp65-LAMP1 induced proliferation of pp65-specific CD4(+) clones and efficiently induced a pp65-specific CD4(+) response, suggesting that after DC maturation the intracellular processing machinery for class II remains intact for at least 16 h. Moreover, infection of DCmat with rVV-Sig-pp65-LAMP1 resulted in at least equivalent presentation to CD8(+) cells as infection with rVV-pp65. These results demonstrate that despite rVV interference with DCimm maturation, a single targeting vector can deliver Ags to DCmat for the effective simultaneous stimulation of both CD4(+) and CD8(+) cells.

Alterations of the p53 and pRB pathways in human astrocytoma

Human astrocytomas are characterized by a number of molecular changes affecting two critical tumor suppressor pathways: the pRB and the p53 pathways. Genetic alterations functionally eliminate pRB and p53 themselves or upstream and/or downstream molecules such as products of the Ink4a/ARF locus, p16Ink4a and p14ARF. As a result, malignant cells are defective in critical cell cycle and apoptosis regulatory elements contributing to unrelenting tumour growth and invasion. Current research aims to discover effective means of reconstituting p53 and pRB pathway components in an effort to attenuate the aggressive phenotype of astrocytoma.

Discovery of a novel member of the histamine receptor family

We report the discovery, tissue distribution and pharmacological characterization of a novel receptor, which we have named H4. Like the three histamine receptors reported previously (H1, H2, and H3), the H4 receptor is a G protein-coupled receptor and is most closely related to the H3 receptor, sharing 58% identity in the transmembrane regions. The gene encoding the H4 receptor was discovered initially in a search of the GenBank databases as sequence fragments retrieved in a partially sequenced human genomic contig mapped to chromosome 18. These sequences were used to retrieve a partial cDNA clone and, in combination with genomic fragments, were used to determine the full-length open reading frame of 390 amino acids. Northern analysis revealed a 3.0-kb transcript in rat testis and intestine. Radioligand binding studies indicated that the H4 receptor has a unique pharmacology and binds [(3)H]histamine (K(d) = 44 nM) and [(3)H]pyrilamine (K(d) = 32 nM) and several psychoactive compounds (amitriptyline, chlorpromazine, cyproheptadine, mianserin) with moderate affinity (K(i) range of 33-750 nM). Additionally, histamine induced a rapid internalization of HA-tagged H4 receptors in transfected human embryonic kidney 293 cells.

Effects of bile salts on cholestan-3beta,5alpha,6beta-triol-induced apoptosis in dog gallbladder epithelial cells

Oxysterols are cytotoxic agents. The gallbladder epithelium is exposed to high concentrations of oxysterols, and so elucidating the mechanisms of cytotoxicity in this organ may enhance our understanding of the pathogenesis of biliary tract disorders. We investigated the cytotoxic effects of the oxysterol cholestan-3beta,5alpha,6beta-triol (TriolC) on dog gallbladder epithelial cells. Apoptosis was the major form of cytotoxicity, as determined by analysis of nuclear morphologic changes and by multiparameter flow cytometry. Hydrophobic bile salts are known to have cytotoxic effects, whereas hydrophilic bile salts have cytoprotective effects. We therefore examined whether the hydrophobic bile acid taurodeoxycholic acid (TDC) and the hydrophilic bile acid tauroursodeoxycholic acid (TUDC) had modifying effects on oxysterol-induced cytotoxicity. TriolC caused an increase in the number of apoptotic cells from 14+/-11% (control) to 48+/-12% of total cells (P<0.01). After combining TriolC with TDC, cell apoptosis increased to 63+/-16% (P<0.05), whereas after addition of TUDC, the number of apoptotic cells decreased to 31+/-12% (P<0.05) of total cells. In summary, oxysterols such as TriolC induce apoptosis. Hydrophobic bile salts enhance TriolC-induced apoptosis, whereas hydrophilic bile salts diminish TriolC-induced apoptosis. These results suggest that interactions between oxysterols and bile salts play a role in the pathophysiology of biliary tract disorders.

Anatomical study of the pyramidal process of the palatine bone in relation to implant placement in the posterior maxilla

The placement of dental implants in the molar region of the maxilla is often difficult because of insufficient bone volume and the inferior bone quality. In order to avoid these limitations, the pillar of bone, which is composed of the maxillary tuberosity, the pyramidal process of the palatine bone and the pterygoid process of the sphenoid bone, was introduced for implant placement. In fact, the pyramidal process is the posterior structure where implants are placed but until now, there is no available data of the size or shape of the pyramidal process. Therefore, we measured the height, anteroposterior distance and mediolateral distance of the pyramidal process and observed the shape of lateral and posterior surfaces of the pyramidal process of 54 Korean edentulous dry skulls in this study. The height was 13.1 mm (male: 13.6 mm, female: 12.4 mm). The anteroposterior distance was 6.5 mm (male: 6.7 mm, female: 6.1 mm). The mediolateral distance was 9.5 mm (male: 9.9 mm, female: 9.0 mm). The most common type was the right-angled triangle in the lateral surface (44.4%) and in the posterior surface (66.7%). There was no statistical significance between the male and the female in all items (P > 0.05). These results provide anatomical features in relation to placement of dental implants in the molar region of the maxilla and would be useful in treatment planning of partially or completely edentulous patients.

Dermatofibrosarcoma protuberans: treatment results of 35 cases

BACKGROUND AND PURPOSE

This study evaluates the treatment results of patients with dermatofibrosarcoma protuberans.

PATIENTS AND METHODS

Between August 1987 and July 1998, 35 consecutive patients with pathologically proved dermatofibrosarcoma protuberans received surgery with or without radiation therapy. Their treatment results were analyzed retrospectively.

RESULTS

The patient ages ranged from 5 to 67 years (median 37 years). There were 24 males and 11 females. The anatomic sites of tumor were: trunk in 21, extremity in eight, and head and neck region in six. The maximal dimension of tumor ranged from 1.5 to 25 cm. Surgery techniques included local excision and wide excision with or without graft or flap. Adjuvant radiation therapy was given to 11 patients, with a dose ranging from 46 to 68 Gy (one pre-operative, ten post-operative). At a median follow-up of 50 months (range 11-131 months), there were 11 patients (nine patients without radiation therapy) who developed local failure. Salvage therapy (excision with or without radiation therapy) was given to all of them, and ten achieved disease control. Some patients had treatment-related moderate cosmetic or functional problems.

CONCLUSIONS

Dermatofibrosarcoma protuberans is a malignancy of a high cure rate, and adjuvant radiation therapy can reliably decrease the local recurrence rate and prevent mutilation and functional deficit caused by repeated surgery.

Oligomerization of dopamine and serotonin receptors

Until recently, it has largely been assumed that G protein-coupled receptors (GPCRs) function as monomeric entities. However, over the past few years, we and others have documented that GPCRs can form dimers and oligomers, leading to a re-evaluation of the mechanisms thought to mediate GPCR function. Despite the growing number of investigations into dimerization, little is known about the structural basis of receptor-receptor interactions and the functional consequences of dimer formation. Here, we present a brief review of some insights we have gained into the dimerization of dopamine and serotonin receptors. We have demonstrated that agonist-regulated trafficking is identical for receptor monomers and dimers, however, agonist treatment appears to stabilise the receptor oligomers. An investigation of the structural assembly between receptors involved in dimerization showed that there are several sites of interaction including hydrophobic transmembrane domain interactions and intermolecular disulphide bonds. We have also examined receptor hetero-oligomerization and demonstrated the potential for novel functions as a result of these associations. Finally, as a result of these observations, we have been able to present evidence that GPCRs function as oligomers in the cell.

Anaerobic bacteria and intrahepatic stones: detections of Clostridium sp. and Bacteroides fragilis

OBJECTIVE

To detect anaerobic bacteria Clostridium sp. and Bacteroides fragilis in intrahepatic stones by molecular genetic method.

METHODS

DNA was extracted from 59 stone samples and subjected to polymerase chain reaction (PCR) amplification targeting the 16S rRNA gene of Clostridium sp. and the glutamine synthetase gene of Bacteroides fragilis. Single-strand conformational polymorphism (SSCP) analysis was performed to identify the Clostridium sp.

RESULTS

16S rRNA gene sequences for Clostridium sp. were identified in 49 stones (83%, 49/59). The two most common groups were detected in 19 (41%) and 17 (37%) of the 46 samples using SSPC analysis, and 25/59 (42%) stones were tested positive for Bacteroides fragilis.

CONCLUSIONS

Anaerobes such as Clostridium sp. and Bacteroides fragilis present in intrahepatic stones and may play a role in stone formation. PCR is a useful technique to detect fastidious pathogens, which are difficult to culture. SSCP of PCR products is a rapid method in differentiating bacterial species.

Apical gene transfer into quiescent human and canine polarized intestinal epithelial cells by lentivirus vectors

Intestinal epithelial cells secrete a protective luminal mucus barrier inhibiting viral gene transfer. Quiescent, polarized monolayers of primary epithelial cells from dog gallbladder and human colon are efficiently transduced through the apical mucus side by lentivirus vectors, suggesting their application to intestinal gene therapy.

Cholestan-3beta,5alpha,6beta-triol, but not 7-ketocholesterol, suppresses taurocholate-induced mucin secretion by cultured dog gallbladder epithelial cells

In order to investigate oxysterol-mediated effects on the biliary system, we studied the effects of cholestan-3beta,5alpha,6beta-triol (TriolC) and 7-ketocholesterol (7KC) on gallbladder epithelial cells. We compared their cell proliferation effects in cultured dog gallbladder epithelial cells (DGBE) to their effects in cultured human pulmonary artery endothelial cells (HPAE). Oxysterols inhibited cell proliferation in a dose-dependent fashion. Oxysterols inhibited cell growth to 50% of control at a higher dose for DGBE cells than for HPAE cells. TriolC was more cytotoxic than 7KC. We also investigated the effect of oxysterols on bile salt-induced mucin secretion by DGBE cells. TriolC suppressed mucin secretion by DGBE cells, whereas 7KC did not. These findings support the hypothesis that biliary oxysterols affect gallbladder mucosal function.

Second malignant tumors in patients with nasopharyngeal carcinoma and their association with Epstein-Barr virus

Since previous published studies about second malignant tumors (SMTs) in nasopharyngeal carcinoma (NPC) patients usually included a limited sample size and did not attain consistent results, we conducted a large retrospective study in a cohort of 1,549 patients to assess the risk of SMT in NPC patients following radiotherapy (RT) in Taiwan. The follow-up period ranged from 2 to 16 years, with a median of 7 years. Thirty-nine patients developed SMTs during the 7,145 person-year follow-up [standardized incidence ratio (SIR): 2. 8; 95% confidence interval (CI): 2.0 to 3.9]. Increased risks of developing SMTs were observed for head and neck (H/N) cancer (SIR: 16.5; 95% CI: 10.0 to 26.8), gastric cancer (SIR: 5.5; 95% CI: 2.2 to 11.4) and leukemia (SIR: 9; 95% CI: 1.9 to 26.3). Paraffin-embedded specimens of secondary H/N cancer (11), secondary gastric cancer (6) and their corresponding NPC specimens were examined by EBER in situ hybridization to assess the association between Epstein-Barr virus (EBV) and these SMTs. Twenty-six primary H/N and 5 gastric cancer specimens were chosen as the control groups. In H/N cancer, EBV was detected in 3.8% of the primary cancers and 9.1% of the secondary cancers. All the positive specimens resulted from hypopharyngeal cancer. Of the secondary gastric cancers, only 1 case (16.6%) was associated with EBV. None of the primary gastric cancers was associated with EBV. Our results indicate an increased risk of developing SMTs, with a preference for head and neck cancer, gastric cancer and leukemia, in NPC patients after RT in Taiwan. Only a small proportion of the secondary H/N and gastric cancers was associated with EBV.

Comparison of clinical behaviors and responses to radiation between squamous cell carcinomas and adenocarcinomas/adenosquamous carcinomas of the cervix

BACKGROUND

Adenocarcinomas/adenosquamous carcinomas (AC/ASC) are relatively uncommon histological subtypes in cervical cancer. In this study, we retrospectively compared the clinical behaviors and responses to radiation of squamous cell carcinomas (SCC) and AC/ASC in patients with stage I-IVA cervical cancer primarily treated by radiotherapy (RT).

METHODS

Nine hundred twenty-eight patients with cervical cancer primarily treated with RT were included in this study. Ninety-four percent of the patients had SCC and 6% had AC/ASC. The association of histological subtype to various clinical parameters was assessed. Tumor response and failure patterns were analyzed, and the prognostic significance of histological subtype and other clinical parameters were evaluated by univariate and multivariate analyses.

RESULTS

(1) Patients with AC/ASC had a significantly higher percentage of bulky I-IIA disease, a younger age (< 45 years), and an elevated carcinoembryonic antigen (CEA) level, but a lower percentage of elevated squamous cell carcinoma antigen (SCC-Ag) level, than patients with SCC. Hemoglobin (Hb) levels and lymph node status were not significantly different between SCC and AC/ASC patients. (2) A higher percentage of AS/ASC patients had residual induration 2 to 3 months after RT than those with SCC (40% vs. 21.6%, p = 0.008). Higher local failure rates were found for AC/ASC patients compared to SCC patients (38% vs. 15%, p = 0.001). (3) The 5-year disease-specific survival rate was 66% and 50% for SCC and AC/ASC patients, respectively (p = 0.016). Advanced stages, Hb levels lower than 10 g/dl, positive lymph nodes, AC/ASC histological subtype, and SCC-Ag levels higher than 10 ng/ml were independent prognostic factors for worse survival for all patients. For patients with AC/ASC in particular, only stage and positive lymph nodes were significant prognostic factors.

CONCLUSION

Cervical cancer patients with AC/ASC are relatively younger and have a higher incidence of elevated CEA and a lower incidence of elevated SCC-Ag levels than those with SCC. For AC/ASC patients, the tumor responses to RT were relatively slow and poor. This group of patients had a worse survival rate than patients with SCC, mainly because of the higher incidence of uncontrolled local disease for AC/ASC patients.

Elective neck irradiation for nasopharyngeal carcinoma

BACKGROUND

This study was conducted to evaluate the effectiveness of elective neck irradiation (ENI) for nasopharyngeal carcinoma (NPC), and to analyze factors associated with ENI failure.

METHODS

A radiation port covering the side of a neck without gross nodal metastasis was qualified for evaluation of the effectiveness of ENI. From 1988 through 1992, a total of 261 patients with N0 (130 cases), N1 (91 cases), and N3 (40 cases) NPCs were studied. All patients were irradiated with 60Co teletherapy or 10 MV x-ray to a total dose of 46.8 Gy/26 fractions, followed by a boost treatment to the primary site to a total dose of 64.8 to 75.6 Gy/36-42 fractions. All ENI ports received irradiation to a dose of 46.8 to 60.8 Gy. The duration of follow-up was 6 to 10 years, with a median of 8.1 years. Factors associated with to the risk of ENI failure were analyzed.

RESULTS

(1) The overall 5-year actuarial local control rate and actuarial survival rate were 74% and 63%, respectively. (2) Among the 261 cases in which ENI treatment was used, the treatment failed in 12 cases, accounting for a crude ENI failure rate of 5%. The overall 5- and 10-year cumulative risk of ENI failure was 5% and 7%, respectively. (3) Time from the start of treatment to ENI failure ranged from 9 to 66 months, with a median of 17 months. (4) Of the 12 patients for whom EMI failed, 11 (92%) had recurrence in the upper neck, and one in the lower neck. (5) Existence of prior failure at the primary site was the only factor significantly correlated with the risk of ENI failure (p < 0.001). The 5-year cumulative risk of ENI failure for patients with local failure vs. those without was 16% vs. 1% (p < 0.0001).

CONCLUSION

Moderate-dose ENI was highly effective in the control of subclinical disease in the neck for NPC. ENI failure was closely associated with prior failure at the primary site, implying that local primary tumor failure may lead to an increased potential for metastasis to the neck.

CTL control of EBV in nasopharyngeal carcinoma (NPC): EBV-specific CTL responses in the blood and tumors of NPC patients and the antigen-processing function of the tumor cells

Undifferentiated nasopharyngeal carcinoma (NPC) is latently infected with EBV and expresses a restricted number of viral proteins. Studies in healthy virus carriers have demonstrated that at least some of these proteins can act as targets for HLA class I-restricted CTLs. Therefore we have explored the possibility of a CTL-based therapy for NPC by characterizing EBV-specific CTL responses in 10 newly diagnosed NPC cases and 21 healthy virus carriers from Southeast Asia. Using the autologous EBV-transformed lymphoblastoid cell line, virus-specific CTL were reactivated in vitro from PBMC, cloned, and screened for cytotoxicity against target cells expressing individual EBV proteins from recombinant vaccinia vectors. EBV-specific CTLs were identified in 6 of 10 patients and 14 of 21 controls and mainly targeted the EBV nuclear Ag 3 (EBNA3) family of viral latent proteins. However, in 3 of 10 patients and 11 of 21 controls, CTLs specific for the NPC-associated protein LMP2 were also detected, albeit at low frequency. EBV-specific CTLs were detected in tumor biopsy material obtained from 3 of 6 of the patients, indicating that functional CTL are present at the tumor site, but none was specific for tumor-associated viral proteins. To assess the Ag-presenting function in NPC we studied two NPC-derived cell lines (C15 and c666.1) and demonstrated that both were capable of processing and presenting endogenously synthesized protein to HLA class I-restricted CTL clones. Overall, our data provide a sound theoretical basis for therapeutic strategies that aim to boost or elicit LMP2-specific CTL responses in NPC patients.