Analysis of refractive state ratios and the onset of myopia

PURPOSE

To develop formulae for the refractive state ratios, axial length growth and the age of onset (A*) of myopia. Calculated results are compared with measurements.

METHODS

Using an image equation, the axial length in the ametropic state (L) is related to the length in the emmetropic state (L*) and refractive error (D) by a rate of change M (D mm(-1)). Three refractive state ratios are defined: C1 = L/r1, C2 = L/L* and C3 = L/H, where r1 and H are the anterior surface radius of the cornea and the transverse dimension of the eye, respectively. The age of onset A* is calculated by the rate of change of refractive error (M) and the axial growth rates N and N* in the ametropic and emmetropic states, respectively.

RESULTS

The three ratios C1, C2 and C3 are increasing function of the myopia power, for example, C1 = 3.4, 3.1, 2.9 for D = -8, 0, +4 dioptres, respectively. The calculated C1* (for the emmetropic state) varies between 3.08 and 3.14, depending on corneal shape, and C3 = 0.985, 1.0, 1.04 for D = +3, 0, -3 dioptres: these values are consistent with measured data. For a typical system with effective focal length F = 22.25 mm, L* = 24.2 mm and L = 23.4, 24.9, 25.9 mm for D = +2, -2, -5 dioptres, respectively. The calculated rates of change of refractive error M = 2.3-2.9 D mm(-1) for F = 22-23 mm are also consistent with measured values 2.4-2.7 D mm(-1). The age of onset A* is calculated to be proportional to 1/(M dN), where dN = N-N* is the axial growth rate difference between the ametropic and emmetropic states and may be used as a better predictor for myopia onset than the conventional ratio L/r1. The A* is given by the crossing of L and L* curves, in which myopia onset occurs earlier for larger M dN.

CONCLUSION

The theory provides formulae to calculate various refractive state ratios, which are consistent with measurements. By defining two rate functions, M and N, the onset of myopia can be predicted.

The osteoporotic spine

Osteoporotic vertebral fractures represent the most common type of osteoporotic fracture. They can cause significant morbidity and mortality, including physical, functional, and psychosocial impairments. Screening using fracture risk assessments can identify those at greatest risk. Medical and non-medical comprise appropriate, comprehensive treatment programs. The minimally invasive spine procedures vertebroplasty and kyphoplasty can help to significantly reduce pain and deformity in patients with severe pain and deformity from vertebral fracture.

Laparoscopic bilateral nephroureterectomy and bladder cuff excision for native renal pelvic and ureteral transitional cell carcinoma after renal transplantation

A 37-years-old female who was suffering from end-stage renal disease for about 6 years received allograft renal transplantation 4 years ago. She has been receiving 50mg of Cyclosporin A orally daily for immuno-suppression since then. Gross haematuria was noted and computerised tomography showed native left renal pelvic and ureteral multi-focal transitional cell carcinoma with severe hydronephrosis. Laparoscopic bilateral nephroureterectomy and bladder cuff excision were performed. In the past, history of previous operation was considered a relative contraindication for laparoscopic surgery. To our knowledge, we present the first case of laparoscopic treatment for native renal pelvic and ureteral transitional cell carcinoma after renal allograft transplantation without a hand-assisted device. This case shows the feasibility of laparoscopic bilateral nephroureterectomy in patients with transplanted kidneys.

Associations of plasma aflatoxin B1-albumin adduct level with plasma selenium level and genetic polymorphisms of glutathione S-transferase M1 and T1

Mortality from hepatocellular carcinoma (HCC) is extraordinarily high in Matzu, an island off the coast of Southeastern China. To investigate factors associated with plasma aflatoxin B1 (AFB1)-albumin adduct level, we studied 304 healthy adult residents from Matzu. AFB1-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen status by enzyme immunoassay, genotypes of glutathione S-transferase (GST) M1 and T1 by polymerase chain reaction, plasma selenium by atomic absorption spectrometry, and plasma retinol, alpha-tocopherol, alpha-carotene, and beta-carotene levels by high-performance liquid chromatography. Men had higher AFB1-albumin adduct levels than women. GSTM1-nonnull and GSTT1-null genotypes and low plasma selenium level were significantly associated with an increased level of AFB1-albumin adducts among men, whereas age was significantly correlated with adduct level among women. High intake of fermented beans was associated with an increased adduct level among men and women. The inverse associations between plasma selenium level and AFB1-albumin adducts were statistically significant among those with null genotypes of GSTM1 and GSTT1, but not among the nonnull genotypes. This study provides insight into the dietary and genetic factors influencing AFB1-albumin adduct formation in an isolated population with high liver cancer mortality.

Prospective study of Helicobacter pylori eradication therapy in stage I(E) high-grade mucosa-associated lymphoid tissue lymphoma of the stomach

PURPOSE

High-grade mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach are generally believed to be Helicobacter pylori-independent, autonomously growing tumors. However, anecdotal cases of regression of high-grade lymphomas after the cure of H pylori infection had been described. The present prospective study was conducted to evaluate the effect of anti-H pylori therapy in stage I(E) high-grade gastric MALT lymphomas.

PATIENTS AND METHODS

Sixteen patients with H pylori infection and stage I(E) gastric high-grade MALT lymphoma consented to a brief antibiotic therapy as first-line treatment from June 1995 through April 2000. Then, patients underwent intensive endoscopic follow-up examinations (+/- endoscopic ultrasonography) with biopsy to evaluate tumor response. Patients with significant improvement of gross lesions that accompanied regression of large cells were followed up without additional treatment. Patients without significant improvement were immediately referred to systemic chemotherapy.

RESULTS

Eradication of H pylori was achieved in 15 patients and was accompanied by rapid gross tumor regression and disappearance of large cells in 10. All 10 of these patients with early response had subsequent complete histologic remission of lymphoma. The complete remission rate was 62.5% (95% confidence interval, 35.8% to 89.1%). The response rate was not affected by the tumor grading (proportion of large blast cells within the tumor) but was adversely affected by the depth of tumor invasion. At a median follow-up of 43.5 months (range, 21.1 to 67.4 months), all 10 of these patients remained lymphoma-free. The median duration of complete response was 31.2 months (range, 14.4 to 49.1 months).

CONCLUSION

These results suggest that high-grade transformation is not necessarily associated with the loss of H pylori dependence in early-stage MALT lymphomas of the stomach.

Identification of a region critically involved in the interaction of phlorizin with the rabbit sodium-D-glucose cotransporter SGLT1

In order to define potential interaction sites of SGLT1 with the transport inhibitor phlorizin, mutagenesis studies were performed in a hydrophobic region of loop 13 (aa 604-610), located extracellularly, close to the C-terminus. COS 7 cells were transiently transfected with the mutants and the kinetic parameters of alpha-methyl-D-glucopyranoside (AMG) uptake into the cells were investigated. Replacement of the respective amino acids with lysine reduced the maximal uptake rate: Y604K showed 2.2%, L606K 48.4%, F607K 15.1%, C608K 13.1%, G609K 14.1%, and L610K 17.2% of control. In all mutants the apparent K(i) for phlorizin increased at least by a factor of 5 compared to the wild-type K(i) of 4.6 +/- 0.7 micromol/l; most striking changes were observed for Y604K (K(i) = 75.3 +/- 19.0 micromol/l) and C608K (K(i) = 83.6 +/- 13.9 micromol/l). Replacement of these amino acids with a nonpolar amino acid instead of lysine such as in Y604F, Y604G and C608A showed markedly higher affinities for phlorizin. In cells expressing the mutants the apparent affinity of AMG uptake for the sugar was not statistically different from that of the wild type (Km = 0.8 +/- 0.2 mmol/l). These studies suggest that the region between amino acids 604 and 610 is involved in the interaction between SGLT1 and phlorizin, probably by providing a hydrophobic pocket for one of the aromatic rings of the aglucone moiety of the glycoside.

Color Doppler sonography for ventral hernias in patients with acute abdomen: preliminary findings

PURPOSE

We assessed the usefulness of color Doppler sonography (CDUS) in evaluating the vascular status of ventral hernias and distinguishing incarcerated from nonincarcerated ventral hernias.

METHODS

In this prospective study, 10 patients who presented with acute abdomen and had ventral hernias underwent CDUS from August 1999 to May 2000. Patient age and sex and the clinical severity, mode of therapy, and outcome in these 10 patients were evaluated in relationship to the CDUS findings.

RESULTS

Five patients had readily visible flow in the bowel within the hernial sac on CDUS. Two of these 5 had spontaneous reduction under conservative treatment, and 3 had asymptomatic ventral hernias with acute abdomen caused by spontaneous bacterial peritonitis. Barely visible flow was visualized in the bowel by CDUS in 4 other patients. Three of these underwent emergency surgery because of peritoneal signs; 2 of them were found to have ischemic changes in the bowel. The fourth patient underwent a successful manual reduction. The remaining patient had absent flow in the bowel on CDUS and underwent emergency surgery, which revealed gangrenous changes in the bowel.

CONCLUSIONS

The intensity of the Doppler signals on CDUS appears to be a promising predictor of bowel viability in cases of ventral hernia. Thus, CDUS should impact the determination of the treatment plan, including whether to provide conservative treatment or surgery.

Light-emitting carbazole derivatives: potential electroluminescent materials

Stable carbazole derivatives that contain peripheral diarylamines at the 3- and 6-positions and an ethyl or aryl substituent at the 9-position of the carbazole moiety have been synthesized via palladium-catalyzed C-N bond formation. These new carbazole compounds (carbs) are amorphous with high glass transition temperatures (T(g), 120-194 degrees C) and high thermal decomposition temperatures (T(d) > 450 degrees C). The compounds are weakly to moderately luminescent in nature. The emission wavelength ranges from green to blue and is dependent on the substituent at the peripheral nitrogen atoms. Two types of light-emitting diodes were constructed from carb: (I) ITO/carb/TPBI/Mg:Ag and (II) ITO/carb/Alq(3)/Mg:Ag, where TPBI and Alq(3) are 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene and tris(8-hydroxyquinoline) aluminum, respectively. In type I devices, the carb functions as the hole-transporting as well as emitting material. In type II devices, either carb, or Alq(3) is the light-emitting material. Several green light-emitting devices exhibit exceptional maximum brightness, and the physical performance appears to be better than those of typical green light-emitting devices of the structure ITO/diamine/Alq(3)/Mg:Ag. The relation between the LUMO of the carb and the performance of the light-emitting diode is discussed.

Immunohistochemical evaluation of cadherin and catenin expression in early gastric carcinomas: correlation with clinicopathologic characteristics and Helicobacter pylori infection

Dysfunction of E-cadherin and catenin has been linked to invasiveness and differentiation of tumors. This study aimed to characterize the expression of cadherins and catenins in early gastric carcinoma and their relationship to clinicopathologic characteristics and Helicobacter pylori infection. E-cadherin and alpha-, beta- and gamma-catenins were strongly expressed in normal epithelium but abnormal immunoreactivity of at least one of these four proteins was noted in 48 (90.6%) of 53 early gastric carcinomas. Only 5 cases with intestinal-type tumors had intact expression of E-cadherin and alpha-, beta-, and gamma-catenins. Abnormal immunoreactivity in the tumor tissue was observed in 18 patients (34.0%) for E-cadherin, in 35 (66.0%) for alpha-catenin, in 20 (37.7%) for beta-catenin, and in 37 (69.8%) for gamma-catenin. In diffuse-type tumors, abnormal expression of E-cadherin (60.9 vs. 13.3%, p < 0.0005), alpha-catenin (82.6 vs. 53.3%, p < 0.05) and gamma-catenin (91.3 vs. 53.3%, p < 0.005) was more frequent than in the intestinal type. Ten tumors with lymph node metastasis showed a relatively higher frequency of abnormal expression of E-cadherin (70 vs. 25.6%, p < 0.05) but a lower frequency of abnormal expression of beta-catenin (10 vs. 44.1%, p = 0.07) than those without metastasis. No significant association was found between cadherin/catenin expression and the depth of invasion or the H. pylori status. It was concluded that abnormal expression of E-cadherin and the catenin-mediated cell-cell adhesion system occurs frequently in early gastric carcinogenesis and may play an important role in the genesis of histologic differentiation and in the mode of metastasis of early gastric carcinomas.

Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions

Curcumin (diferuloylmethane), a yellow substance from the root of the plant Curcuma longa Linn., has been demonstrated to inhibit carcinogenesis of murine skin, stomach, intestine and liver. However, the toxicology, pharmacokinetics and biologically effective dose of curcumin in humans have not been reported. This prospective phase-I study evaluated these issues of curcumin in patients with one of the following five high-risk conditions: 1) recently resected urinary bladder cancer; 2) arsenic Bowen's disease of the skin; 3) uterine cervical intraepithelial neoplasm (CIN); 4) oral leucoplakia; and 5) intestinal metaplasia of the stomach. Curcumin was taken orally for 3 months. Biopsy of the lesion sites was done immediately before and 3 months after starting curcumin treament. The starting dose was 500 mg/day. If no toxicity > or = grade II was noted in at least 3 successive patients, the dose was then escalated to another level in the order of 1,000, 2,000, 4,000, 8,000, and 12,000 mg/day. The concentration of curcumin in serum and urine was determined by high pressure liquid chromatography (HPLC). A total of 25 patients were enrolled in this study. There was no treatment-related toxicity up to 8,000 mg/day. Beyond 8,000 mg/day, the bulky volume of the drug was unacceptable to the patients. The serum concentration of curcumin usually peaked at 1 to 2 hours after oral intake of crucumin and gradually declined within 12 hours. The average peak serum concentrations after taking 4,000 mg, 6,000 mg and 8,000 mg of curcumin were 0.51 +/- 0.11 microM, 0.63 +/- 0.06 microM and 1.77 +/- 1.87 microM, respectively. Urinary excretion of curcumin was undetectable. One of 4 patients with CIN and 1 of 7 patients with oral leucoplakia proceeded to develop frank malignancies in spite of curcumin treatment. In contrast, histologic improvement of precancerous lesions was seen in 1 out of 2 patients with recently resected bladder cancer, 2 out of 7 patients of oral leucoplakia, 1 out of 6 patients of intestinal metaplasia of the stomach, I out of 4 patients with CIN and 2 out of 6 patients with Bowen's disease. In conclusion, this study demonstrated that curcumin is not toxic to humans up to 8,000 mg/day when taken by mouth for 3 months. Our results also suggest a biologic effect of curcumin in the chemoprevention of cancer.

Obstructive jaundice caused by hepatocellular carcinoma: detection by endoscopic sonography

Tumor thrombus in the extrahepatic biliary tree is a rare mechanism of obstructive jaundice. We present a patient with a minute hepatocellular carcinoma in the caudate lobe that invaded the common hepatic duct and caused biliary obstruction. Endoscopic sonography showed a tumor thrombus with central echogenicity and a "nodule-in-nodule" pattern and suggested the correct diagnosis.

Molecular analysis of mucosa-associated lymphoid tissue (MALT) lymphoma of ocular adnexa

Lymphomas of mucosa-associated lymphoid tissue (MALT) are a distinct subgroup of extranodal B-cell non-Hodgkin's lymphomas. Most studies have failed to demonstrate the clonal rearrangement of BCL-1, BCL-2 or c-MYC genes for MALT lymphomas. Further, alteration of the p53 gene is rarely demonstrated in low-grade MALT lymphomas, but can be detected in high-grade disease. Lymphomas of the ocular adnexa represent approximately eight percent of all extranodal lymphomas, most of which are MALT lymphomas, but few studies had explored the alterations of BCL-1, BCL-2, c-MYC and p53 genes specifically for ocular MALT lymphomas. We investigated the changes to BCL-1, BCL-2, c-MYC and p53 genes in these lymphomas for Taiwanese patients. Clonal rearrangement for immunoglobulin heavy-chain (IgH), BCL-1, BCL-2, c-MYC and p53 genes was examined for 16 cases of ocular MALT lymphoma. Restriction-length polymorphism and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the DNA, corresponding to exons 5 through 9, followed by DNA sequencing, were utilized to analyze the possible mutations of the p53 gene for these tumors. Thirteen of the cases revealed rearranged IgH genes using Southern blotting or PCR. No rearrangement of BCL-1, BCL-2, c-MYC or p53 genes was discovered, with point mutation of the p53 gene in one case. As for other types of MALT lymphomas, BCL-1, BCL-2 and c-MYC genes are not implicated in the pathogenesis of the ocular sub-group. Although alteration of the p53 gene is rare for low-grade ocular MALT lymphoma, its role in disease progression merits further research.

Necrotizing fasciitis of the head and neck: an analysis of 47 cases

Necrotizing fasciitis is an overwhelming infection common to the perineum, abdominal wall, and extremities. It is a surgical emergency related to a high mortality rate that is more often seen in elderly and immunocompromised patients. Necrotizing fasciitis occurs uncommonly in the head and neck region. Over a 12-year period, 47 cases of necrotizing fasciitis of the head and neck region were collected at this hospital. The demographics, predisposing factors, clinical presentation and courses, management, complications, and outcomes were analyzed. The cases were divided into two groups: survivors and nonsurvivors. Statistical comparisons were made of the parameters age, gender, smoking or drinking habit, underlying medical problems, laboratory data, and treatments used. Forty-two patients (89.4 percent) had associated systemic disease; most of these patients had diabetes (72.3 percent). The clinical manifestations are nonspecific but are often typical for diagnosis. The necessity of computed tomographic scans is not conclusive in this study. Presentation of septic shock (p = 0.004) and association with underlying malignancy (p = 0.03) were the only statistically significant factors that led to a poor prognosis. The cornerstones of proper management include early diagnosis, aggressive surgical debridement, broad-spectrum antibiotics, and intensive supportive care.

Paraneoplastic cerebellar degeneration as the first manifestation of cancer

Paraneoplastic cerebellar degeneration (PCD) is a type of paraneoplastic syndrome that primarily affects women with gynecological cancers. Patients typically experience pancerebellar symptoms, including gait ataxia, dysarthria, nystagmus, and truncal and appendicular ataxia. We present the case of a 50-year-old woman with PCD and presumed ovarian cancer who initially complained of ataxia and dysarthria. PCD was diagnosed on the basis of her symptoms, diagnostic imaging, and laboratory work. PCD symptoms may precede the diagnosis of malignancy by months or years. Early diagnosis and treatment of these syndromes, including rehabilitation, may result in improvements in quality of life for this population of patients.

Tumor angiogenesis and its possible role in intravasation of colorectal epithelial cells

PURPOSE

To determine whether an increase in tumor angiogenesis facilitates intravasation of colorectal epithelial cells, we compared intratumoral microvessel counts with the presence of circulating colorectal epithelial cells in the portal venous blood from patients with colorectal carcinomas.

EXPERIMENTAL DESIGN

Circulating colorectal epithelial cells were detected by a reverse transcription-PCR assay to amplify guanylyl cyclase C (GCC) transcripts. The extent of tumor vascularization was quantitatively assessed by immunohistochemical staining with anti-CD31 antibody.

RESULTS

Colorectal epithelial cells (as measured by GCC mRNA expression) were detected in the portal venous blood in 30 of 58 patients (52%). The mean (+/- SD) microvessel count in the tumors from patients with expression of GCC mRNA in their portal venous blood was 82.74 +/- 24.97. The corresponding values in the tumors from patients without expression of GCC mRNA in portal venous blood was 65.96 +/- 19. For each 10-microvessel increase per x200 field, the risk of colorectal epithelial cell presence in the portal venous blood increased 1.52-fold (95% confidence interval, 1.19-2.12; P = 0.005).

CONCLUSION

High intratumoral vessel count was noted to be a valuable factor for predicting the presence of colorectal epithelial cells in the portal venous blood.

Genetic regulation of autoimmune disease: BALB/c background TGF-beta 1-deficient mice develop necroinflammatory IFN-gamma-dependent hepatitis

Autoimmune hepatitis (AIH) in humans arises spontaneously in genetically susceptible individuals and is associated with the presence of Th1 cells in the liver. The understanding of AIH has advanced more slowly than that of other organ-specific autoimmune diseases, however, largely because of the lack of an appropriate animal model. We now describe a new mouse model characterized by spontaneous development of necroinflammatory hepatitis that is restricted by genetic background. Mice deficient in the immunomodulatory cytokine TGF-beta1 were extensively back-bred to the BALB/c background. The BALB/c background dramatically modified the phenotype of TGF-beta1(-/-) mice: specifically, BALB/c-TGF-beta1(-/-) mice developed a lethal necroinflammatory hepatitis that was not observed in TGF-beta1(-/-) mice on a different genetic background. BALB/c background TGF-beta1(-/-) livers contained large numbers of activated CD4(+) T cells that produced large quantities of IFN-gamma, but little IL-4, identifying them as Th1 cells. BALB/c background TGF-beta1(-/-)/IFN-gamma(-/-) double knockout mice, generated by cross-breeding, did not develop necroinflammatory hepatitis, demonstrating that IFN-gamma is mechanistically required for its pathogenesis. This represents the first murine model of hepatitis that develops spontaneously, is restricted by genetic background, and is dependent upon the Th1 cytokine IFN-gamma, and that thus recapitulates these important aspects of AIH.

K-ras mutation at codon 12 in stage I pancreatic adenocarcinoma: analysis by laser capture microdissection and direct sequencing

Pancreatic ductal adenocarcinoma has been reported to carry a rate mutation high in codon 12 of the K-ras oncogene. To avoid the pitfalls of conventional methods of tissue dissection that might affect the sensitivity and specificity of detecting K-ras mutation, laser capture microdissection (LCM) technique was used. Pancreatic adenocarcinoma tissues were obtained from 15 patients who underwent Whipple's procedure. Selected tissues procured by LCM were analyzed by direct sequencing after polymerase chain reaction amplification of K-ras sequences at codon 12. K-ras mutation was noted in nine patients. All mutations showed G to A substitution at codon 12. The mutational pattern (GGT to GAT) is similar in both western and eastern reports. LCM is a feasible method to effectively obtain pure tumor cells from a surgical specimen. It remains to be determined whether this low mutation rate is a result of relatively early stage of disease or different carcinogenesis in different geographic regions.

Gray-scale and color Doppler sonographic diagnosis of epiploic appendagitis

Depending on its location, epiploic appendagitis may mimic nearly any acute abdominal condition. We present the case of a patient with left lower quadrant pain. Sonography demonstrated an ovoid, hyperechoic, noncompressible lesion at the point of tenderness but no inflammatory changes in the adjacent colonic wall. Color Doppler sonography showed no flow in the lesion. Based on the sonographic diagnosis of epiploic appendagitis, conservative treatment was given, with complete recovery in 5 days. Awareness of these sonographic findings may aid in the early diagnosis of epiploic appendagitis and avoid unnecessary treatment.

The shrinkage-activated Na(+) conductance of rat hepatocytes and its possible correlation to rENaC

At moderate cell shrinkage, activation of Na(+) channels is the most prominent mechanism of regulatory cell volume increase in rat hepatocytes. The amiloride sensitivity of these channels suggests a relation to the family of epithelial Na(+) channels (ENaCs). The present study was performed to determine the pharmacological profile of shrinkage-activated Na(+) channels and to test for ENaC expression in primary cultures of rat hepatocytes; in addition, the influence of the cell volume regulated serine/threonine kinase hSGK on activity and pharmacological profile of rENaC was examined in Xenopus oocytes. Conventional electrophysiology in hepatocytes reveals that the shrinkage-activated Na(+) channel is inhibited by amiloride and EIPA with IC(50) values of 6.0 and 0.12 micromol/l, respectively. Western blots and RT-PCR demonstrate that rat hepatocytes do express all three subunits (alpha, beta, gamma) of ENaC. Coexpression of hSGK with rENaC in Xenopus oocytes reveals that the kinase stimulates ENaC by a factor of 4. Moreover, hSGK decreases the affinity to amiloride (increase of IC(50) from 0.12 to 0.26 micromol/l) and increases the affinity to EIPA (decrease of IC(50) from 250 to 50 micromol/l). In conclusion, rat hepatocytes express ENaC, which is activated by the cell volume-sensitive kinase hSGK. ENaC may contribute to the Na(+) channels activated by osmotic cell shrinkage in hepatocytes, whereby the relatively low amiloride and high EIPA sensitivity of the channel could at least be partially due to modification by SGK, which decreases the amiloride and increases the EIPA sensitivity of ENaC.

Correlation of histologic subtypes and replication error phenotype with comparative genomic hybridization in gastric cancer

To characterize phenotypic and genotypic changes in gastric cancer (GC), DNA copy number aberrations (CNAs) were assessed in 53 tumors using comparative genomic hybridization (CGH) and correlated with clinicopathologic characteristics and status of TP53 and replication error (RER). The number of CNAs per tumor was 6.8 (gain 5.3, loss 1.5), and the number of changes was significantly higher in tumors with advanced stage, TP53 mutation, and without RER than in those with early stage (7.7 vs. 3.0), no TP53 mutations (12.4 vs. 4.8) or RER phenotype (8.2 vs. 2.6). Frequent abnormalities included gains on chromosomal arms 8q (43%), 6q (26%), 11q (26%), 13q (24%), 7p (23%), 17q (23%), and 20q (23%), and losses on chromosomal arms 16q (26%), 19p (23%), 5q (19%), 3p (15%), 4q(15%), and 1p (15%). Advanced GC demonstrated a higher prevalence of gains of 8q (51% vs. 10%, P < 0.05) and loss of 16q (33% vs. 0%, P < 0.05) than early GC. Gains on 8q (64% vs. 20%, P < 0.05), 17q (39% vs. 4%, P < 0.05) and losses on 3p (25% vs. 4%, P = 0.05) and 5q (32% vs. 4%, P < 0.05) were higher in intestinal GC than in diffuse GC. On the other hand, gains on 13q were more common in the diffuse type (40% vs. 11%, P < 0.05). As compared with noncardia cancer, cardia cancer showed more gains on 7p (58% vs. 12%, P < 0.05) and 20q (58% vs. 12%, P < 0.05) and more losses on 4q (50% vs. 5%, P < 0.05). The finding of histology-related aberrations and the combination of CGH and molecular data thus provide additional evidence suggesting genetic heterogeneity of GC.

A flow cell assay for evaluation of whole cell drug efflux kinetics: analysis of paclitaxel efflux in CCRF-CEM leukemia cells overexpressing P-glycoprotein

P-glycoprotein (Pgp) mediates drug accumulation defects in malignant cells in vitro. It confers resistance to multiple drugs including paclitaxel, an agent useful in treating malignancies including acute leukemia. Pgp-mediated drug resistance appears to be due to primary active drug-transport as well as other effects on membrane permeability, but the relative contribution of each is unclear. Flow cells are useful for differentiating transport-mediated efflux from altered membrane permeability, but their utility is limited to attached cells. We developed a novel flow cell to study drug efflux kinetics in suspension culture cells and examined paclitaxel efflux in resistant CEM/VLB100 leukemia cells, which overexpress Pgp, compared with its sensitive CEM parent line. Paclitaxel efflux from both cell lines was described by bi-exponential kinetics. The predominant initial rapid component increased linearly with paclitaxel concentration, consistent with passive efflux, and was faster in CEM/VLB100 than CEM cells. The slow terminal component of efflux was also more rapid for CEM/VLB100 than CEM, and was saturable (V(max)= 9.1 +/- 1.1 versus 3.5 +/- 0.3 pmol/min/10(7) cells, respectively) at a lower paclitaxel concentration than the parental CEM cells (k(m) = 63 +/- 46 nM versus 144 +/- 56 nM, respectively). In CEM/VLB100 cells, this saturable component was inhibited by verapamil and was temperature-sensitive, consistent with Pgp-mediated transport. Verapamil also inhibited the rapid component of efflux, suggesting additional effects on membrane permeability. Our studies show that the present technique is useful for studying drug transport and that effects of Pgp on membrane permeability contribute significantly to the net drug-accumulation defect.

Functional asymmetry of the sodium-D-glucose cotransporter expressed in yeast secretory vesicles

The sodium-D-glucose cotransporter (SGLT1) was expressed in a yeast mutant strain NY 17 (sec6-4) that accumulates secretory vesicles at a nonpermissive temperature because of a block in the delivery of these vesicles to the plasma membrane. By differential centrifugation a microsomal fraction enriched in secretory vesicles was prepared with a high specific activity of the vanadate-sensitive H+-ATPase and invertase. In this membrane fraction one protein band of an apparent molecular weight of 55 kDa representing the nonglycosylated SGLT1 protein could be detected by immunochemical analysis. In addition, higher molecular weight protein bands probably representing dimers and aggregates were found. In transport studies with the microsomes D-glucose fluxes showed asymmetric properties: efflux experiments revealed the typical properties of the SGLT1 such as sodium dependence, inhibition by phlorizin and potential dependence. Influx of D-glucose showed no dependence on sodium and was not inhibited by phlorizin. Furthermore, the transporter exhibited a striking asymmetry with regard to the D-glucose affinity and the sugar specificity. These results suggest that the orientation of the SGLT1 expressed in yeast secretory vesicles is, indeed, inverted with regard to its configuration in the plasma membrane of epithelial cells. Moreover, there are striking functional differences between the periplasmic and cytoplasmic face of the transporter.

Correlation of histologic subtypes and replication error phenotype with comparative genomic hybridization in gastric cancer

To characterize phenotypic and genotypic changes in gastric cancer (GC), DNA copy number aberrations (CNAs) were assessed in 53 tumors using comparative genomic hybridization (CGH) and correlated with clinicopathologic characteristics and status of TP53 and replication error (RER). The number of CNAs per tumor was 6.8 (gain 5.3, loss 1.5), and the number of changes was significantly higher in tumors with advanced stage, TP53 mutation, and without RER than in those with early stage (7.7 vs. 3.0), no TP53 mutations (12.4 vs. 4.8) or RER phenotype (8.2 vs. 2.6). Frequent abnormalities included gains on chromosomal arms 8q (43%), 6q (26%), 11q (26%), 13q (24%), 7p (23%), 17q (23%), and 20q (23%), and losses on chromosomal arms 16q (26%), 19p (23%), 5q (19%), 3p (15%), 4q(15%), and 1p (15%). Advanced GC demonstrated a higher prevalence of gains of 8q (51% vs. 10%, P < 0.05) and loss of 16q (33% vs. 0%, P < 0.05) than early GC. Gains on 8q (64% vs. 20%, P < 0.05), 17q (39% vs. 4%, P < 0.05) and losses on 3p (25% vs. 4%, P = 0.05) and 5q (32% vs. 4%, P < 0.05) were higher in intestinal GC than in diffuse GC. On the other hand, gains on 13q were more common in the diffuse type (40% vs. 11%, P < 0.05). As compared with noncardia cancer, cardia cancer showed more gains on 7p (58% vs. 12%, P < 0.05) and 20q (58% vs. 12%, P < 0.05) and more losses on 4q (50% vs. 5%, P < 0.05). The finding of histology-related aberrations and the combination of CGH and molecular data thus provide additional evidence suggesting genetic heterogeneity of GC.

Acinar cell carcinoma with hypervascularity

Acinar cell carcinoma is an uncommon malignancy with a reported incidence of 1% among exocrine tumors of the pancreas. The case of a 60-year-old Taiwanese man who presented with obstructive jaundice, abdominal pain, and body weight loss is described here. A mixed clinical picture of islet cell tumor and ductal carcinoma of the pancreas was shown to be a hypervascular tumor at the pancreatic head region with an irregular stricture at the common channel of the common bile and pancreatic ducts. The patient had normal levels of plasma carcinoembryonic antigen, carbohydrate antigen 19-9, alpha-fetoprotein, but an increase in plasma levels of insulin and C-peptide. Immunohistochemical stains and electron microscopic examination of the tumor was consistent with acinar cell carcinoma.

Urgent endoscopic nasobiliary drainage without fluoroscopic guidance: A useful treatment for critically ill patients with biliary obstruction

BACKGROUND

Endoscopic nasobiliary drainage (ENBD) is routinely performed under fluoroscopic control. This is a report of our experience with urgent ENBD without fluoroscopic guidance in critically ill patients.

METHODS

Twenty-six critically ill patients who underwent urgent ENBD for biliary obstruction were analyzed. ENBD was performed without fluoroscopic control because of high risk of transportation or inaccessibility of the x-ray facilities. A pig-tailed nasobiliary catheter was inserted into the bile duct with the help of a guidewire under endoscopic control to bypass the site of obstruction. Successful placement was confirmed by free flow of bile on aspiration via the nasobiliary catheter.

RESULTS

A nasobiliary catheter was successfully placed in 23 patients (88%). Adequate bile drainage was achieved in 20 patients with an overall success rate of 77%. There were no procedure-related complications. The mortality rate for patients with successful biliary drainage was 10% (2 of 20), in contrast to 83% (5 of 6) for the group in which drainage was unsuccessful.

CONCLUSIONS

Urgent ENBD is effective for patients with biliary obstruction. With experience, this procedure may be successfully performed in critically ill patients without fluoroscopic guidance at primary care hospitals or intensive care units where fluoroscopic facilities are not readily available.

Biochemical aspects of castor oil biosynthesis

Castor oil is 90% ricinoleate (12-hydroxy-oleate) and has numerous industrial uses. Components of castor bean (Ricinus communis L.) pose serious problems to processors. We are evaluating two complementary approaches to providing a safe source of castor oil.

Abdominal wall necrosis following transcatheter arterial chemoembolization for hepatocellular carcinoma

A 76-year-old man, who had inoperable hepatocellular carcinoma, had been treated with transcatheter arterial chemoembolization (TACE) 11 times, percutaneous ethanol injection therapy three times and conformal radiotherapy once, all in other hospitals. At this admission, he developed myocutaneous necrosis in the right abdominal wall after TACE, via the collateral of the right internal mammary artery (IMA). Necrosis of the abdominal wall was due to ischemic changes caused by embolization of the distal branches of the IMA, which were aggravated by previous radiation therapy. We advise that embolization of the IMA in patients who have received radiotherapy should be avoided, if possible.

Application of peroral cholangioscopy in an endemic area with high prevalence of hepatocellular carcinoma and choledocholithiasis

BACKGROUND/AIMS

Peroral cholangioscopy with a mother-baby scope system has been introduced for two decades. The paper presents the experience of peroral cholangioscopy at a university hospital in Taiwan where the prevalence of hepatocellular carcinoma and choledocholithiasis was high.

METHODOLOGY

A total of 27 sessions of peroral cholangioscopy were performed in 26 patients during a period of 4 years. Of them, 20 patients were for diagnosis and the rest 6 for removing the retained biliary stones.

RESULTS

The overall successful rate was 96.3%. The post-procedure complication rate was 11.5% with 2 cholangitis and 1 gram-negative septicemia. There were a total of 19 successful diagnostic sessions. These resulted in definite histological diagnosis in 5 patients and more precise diagnoses subsequently confirmed by surgery in 5 patients. In the remaining 9 patients with tentative diagnoses, 5 confirmed their diagnoses but 4 patients changed their diagnoses after peroral cholangioscopy. By this procedure, hepatocellular carcinoma and choledocholithiasis can be well identified and differentiated.

CONCLUSIONS

Peroral cholangioscopy is a safe and valuable modality in diagnosing and treating difficult biliary tract disease when handled with care. It is particularly useful in an endemic area with high prevalence of hepatocellular carcinoma and choledocholithiasis.

Non-functioning islet cell tumors of the pancreas--a multicentric clinical study in Taiwan

BACKGROUND/AIMS

Islet cell tumors of the pancreas are rare. Functioning tumors are characterized by the symptoms induced by the hormones they secrete. The clinical behaviors of non-functioning tumors are quite different. In this retrospective study, we scrutinized 16 patients with non-functioning islet cell tumor in three tertiary university hospitals in Taiwan during a 20-year period.

METHODOLOGY

There were 12 women and 4 men with a mean age of 47 years. Body-weight loss, abdominal pain and palpable mass were the most frequent symptoms.

RESULTS

The mean size of these tumors was 8.9 cm in diameter. Ten tumors were located at the tail of pancreas, the other 6 located at the head. Except for hyperbilirubinemia in 2 patients, none of the patients with non-functioning islet cell tumor showed abnormalities of laboratory data including serum tumor markers. Preoperative detection of these tumors by imaging modalities was not difficult due to the large size of the tumors. However, differentiation with functioning tumor or ductal cell carcinoma required clinical and imaging correlation. Fourteen tumors were malignant including 8 with regional lymph nodes involvement, 3 with locally microscopic invasion, 2 with hepatic metastasis and 2 with nearby organ invasion.

CONCLUSIONS

Even with its malignant behavior, non-functioning islet cell tumor still possessed a good prognosis after adequate surgical removal in comparison with a higher mortality rate of ductal carcinoma of the pancreas.

Separation of the molecular species of intact phosphatidylethanolamines and their N-monomethyl and N,N-dimethyl derivatives by high-performance liquid chromatography on a C8 column

We have developed a gradient reversed-phase C8 high-performance liquid chromatography method for the separation of molecular species of phosphatidylethanolamines (PEs) and their N-monomethyl and N,N-dimethyl derivatives. This method uses a 40-min linear gradient of 88-100% methanol, containing ammonium hydroxide as silanol suppressing agent, and is suitable for metabolic studies using both UV detection at 205 nm and radioactivity flow detection. The elution order of a given PE is inversely related to the polarity of its fatty acid constituents. Lipid classes studied here containing the same fatty acyl chains elute in the order: PE-N,N-dimethyl<PE<PE-N-monomethyl<phosphatidylcholine, indicating that elution order is not simply a function of the numbers of methyl groups on the nitrogen atom of PE.

Cellular uptake of dietary flavonoid quercetin 4'-beta-glucoside by sodium-dependent glucose transporter SGLT1

Although it has been suggested that the intestinal glucose transporter may actively absorb dietary flavonoid glucosides, there is a lack of direct evidence for their transport by this system. In fact, our previous studies with the human Caco-2 cell model of intestinal absorption demonstrated that a major dietary flavonoid, quercetin 4'-beta-glucoside, is effluxed by apically expressed multidrug resistance-associated protein-2, potentially masking evidence for active absorption. The objective of this study was to test the hypothesis that quercetin 4'-beta-glucoside is a substrate for the intestinal sodium-dependent D-glucose cotransporter SGLT1. Cellular uptake of quercetin 4'-beta-glucoside was examined with Caco-2 cells and SGLT1 stably transfected Chinese hamster ovary cells (G6D3 cells). Although quercetin 4'-beta-glucoside is not absorbed across Caco-2 cell monolayers, examination of the cells by indirect fluorescent microscopy as well as by HPLC analysis of cellular content revealed cellular accumulation of this glucoside after apical loading. Consistent with previous observations, the accumulation of quercetin 4'-beta-glucoside in both Caco-2 and G6D3 cells was markedly enhanced in the presence of multidrug resistance-associated protein inhibition. Uptake of quercetin 4'-beta-glucoside was greater in SGLT1-transfected cells than in parental Chinese hamster ovary cells. Uptake of the glucoside by Caco-2 and G6D3 cells was sodium-dependent and was inhibited by the monovalent ionophore nystatin. In both Caco-2 and G6D3 cells, quercetin 4'-beta-glucoside uptake was inhibited by 30 mM glucose and 0.5 mM phloridzin. These results demonstrate for the first time that quercetin 4'-beta-glucoside is transported by SGLT1 across the apical membrane of enterocytes.