Use of caffeine as a probe for rapid determination of cytochrome P-450 CYP1A2 activity in humans

AIM

To develop a rapid HPLC method for the determination of cytochrome P-450 CYP1A2 activity.

METHODS

A 300-microL plasma was prepared by extraction with 5-mL chloroform/isopropanol (9:1), and beta-hydroxyletheophylline was added as internal standard (IS). Samples were separated on an ODS column by a gradient elution system, of which mobile phase consisted of 0.05% acetic acid, acetonitrile, and methanol. The compounds of interest were monitored at 282 nm by UV detector.

RESULTS

No potential interfering peaks were found. Paraxanthine (17X), IS and caffeine (137X) were rapidly eluted with baseline resolution, and their retention time was less than 13 min. The detection limits of both 17X and 137X were 0.1 mumol.L-1. Linear relations ranged over 1-100 mumol.L-1 and 1-200 mumol.L-1 with correlation coefficient of 0.9999 and 0.9987, respectively, for 17X and 137X. The coefficients of variation were within 6% for 17X, and 10% for 137X. The average recoveries for both compounds were ranged from 96% to 108%.

CONCLUSION

This method is sensitive and rapid, and can be used for population studies of CYP1A2.

Endoscopic resection of gastrointestinal submucosal tumors

BACKGROUND/AIMS

The occurrence of submucosal tumors in the gastrointestinal tract is not infrequent. According to endoscopic pictures, submucosal tumors can usually be diagnosed without difficulty. However, even with the aid of endoscopic ultrasound, a definite diagnosis is not possible without histological results. Before endoscopy became available, the treatment strategy for gastrointestinal submucosal tumors was either surgery or observation. Due to advances in scientific technology, endoscopic treatment of gastrointestinal submucosal tumors has become increasingly popular. In reviewing the literature, we found that only case reports or small series reports detailing specific tumors in specific locations existed previously.

METHODOLOGY

Endoscopic resection for 12 gastrointestinal submucosal tumors in 11 patients has been successfully performed in our hospital during the past three years.

RESULTS

The group included 5 men and 6 women, ranging in age from 28 to 78 years. The locations of the tumors consisted of 1 in the esophagus, 2 in the stomach, 1 in the jejunum, 5 in the colon and 3 in the rectum. Histological results showed 3 lipomas, 3 carcinoids, 2 leiomyomas, 1 ganglioneuromatous polyp, 1 hemangioma, 1 inflammatory fibroid polyp and 1 myomatous hyperplasia. Bleeding complications occurred in only 2 cases. One stopped spontaneously and the other stopped after epinephrine and sclerosant injection. Only 1 case required a two-step resection in order to avoid perforation. No tumor recurrence was noted during the follow-up period, which ranged from 2 months to 3 years.

CONCLUSIONS

In suitable cases, endoscopic resection of gastrointestinal submucosal tumors can be a safe and valuable method for treating symptomatic tumors and obtaining histological diagnosis of the submucosal tumors.

Colonofiberscopic diagnosis of intestinal tuberculosis

The purpose of this study was to assess the predictive value of colonofiberscopy in the diagnosis of intestinal tuberculosis. The records of more than 14,000 colonofiberscopic examinations performed at the National Taiwan University Hospital from 1971 to 1995 were studied retrospectively. Colonofiberscopic diagnosis of intestinal tuberculosis required at least one of the following: circumferential ulcers, a single transverse axis ulcer with uneven base and elevated or nodular margin surrounded by nodular and hyperemic mucosa, or pseudopolyps. Sixty cases were diagnosed as intestinal tuberculosis based on these criteria, 29 of which were confirmed by histologic or bacteriologic findings or on the basis of clinical response to antituberculosis therapy. The positive predictive value of colonofiberscopy for intestinal tuberculosis was thus 43.3% (95% confidence interval 31-57%). Secondary intestinal tuberculosis with pulmonary tuberculosis accounted for 84% of cases. The most commonly involved area of the gastrointestinal tract was the ileocecal region, followed by the ascending colon and ileum. Based on our findings, colonofiberscopic examination with histopathologic and bacteriologic study of biopsy specimens is a powerful tool for the diagnosis of intestinal tuberculosis.

Requirement of NF-kappaB activation to suppress p53-independent apoptosis induced by oncogenic Ras

The ras proto-oncogene is frequently mutated in human tumors and functions to chronically stimulate signal transduction cascades resulting in the synthesis or activation of specific transcription factors, including Ets, c-Myc, c-Jun, and nuclear factor kappa B (NF-kappaB). These Ras-responsive transcription factors are required for transformation, but the mechanisms by which these proteins facilitate oncogenesis have not been fully established. Oncogenic Ras was shown to initiate a p53-independent apoptotic response that was suppressed through the activation of NF-kappaB. These results provide an explanation for the requirement of NF-kappaB for Ras-mediated oncogenesis and provide evidence that Ras-transformed cells are susceptible to apoptosis even if they do not express the p53 tumor-suppressor gene product.

[An observation on the possible existance of some information transmission between sensory nerve endings of rat]

Dorsal cutaneous branches of the spinal nerves of T5-L1 segments on one side in anaesthesised rats were exposed and cut centrally. One peripheral end of the cut nerves was selected for antidromical stimulation, while an adjacent one for recording, both by Ag-AgCl electrodes. When a train of 50 Hz, 0.2 ms width square waves of 2 s was delivered to the nerve preparation for stimulation, the discharge of the adjacent nerve showed a remarkable increase and then subsided to the original level for about 25 s. Such experiments (n = 414) showed that the induced discharge frequency reached its maximum 2 s after the stimulation and maintained for another 2 s before subsiding to original level in about a period of 25 s. Using the discharge frequency at a certain time segment as an index, the degree of induced discharges of the recorded nerves were linearly related to their spontaneous discharges before stimulation and the sequences of stimulation to some extent. Single square stimulation was unable to induce one-to-one correspondent discharge in the recording nerve. Control experiments were done to rule out the induced discharges being due to the spreading of stimulating current. To summarize the results of all the above experiments, it appeared that some information transmission between sensory nerve endings may be present through some chemical events.

Comparative intraosseal growth of human prostate cancer cell lines LNCaP and PC-3 in the nude mouse

BACKGROUND

More than 75% of patients with advanced prostate carcinoma have skeletal involvement, which is the principal metastatic site and the major complication of this disease. The goal of this work was to compare the osseous metastasis of androgen-sensitive and insensitive prostate cancers in the nude mouse.

MATERIALS AND METHODS

Androgen-sensitive LNCaP or -insensitive PC-3 human prostate carcinoma cells were injected directly into the femur medullas of male nude Beige mice, the animals were then sacrificed at successive time intervals to study the gross and microscopic characteristics of the established tumors.

RESULTS

LNCaP and PC-3 both colonized in the bone marrow within a week, then gradually expanded to the entire bone medulla followed by osseous infiltration to produce obvious symptoms in the affected extremities. Based on the morphology, both osteoblastic and osteolytic changes occurred during the course of tumor progression. In addition, PC-3 tumors eventually broke through the bone cortex, invaded the surrounding tissues, and metastasized to the regional lymph nodes. In contrast, LNCaP remained localized within the bone, and appeared to eventually regress and die after displacing the normal bone marrow cells. Immunohistochemically, LNCaP tumors were consistently positive for prostate-specific antigen in bone metastasis, while PC-3 tumors were negative. Tumor cell nuclei of both PC-3 and LNCaP hybridized to a human repeated sequence DNA probe indicating that the proliferating malignant cells were of human origin.

CONCLUSIONS

These cancer cell lines produced a high incidence of growth in the bone that differed in histogenesis. The relative malignancy of these cell lines was demonstrated in this model.

Colorectal adenoma in patients with a history of breast cancer: a prospective study in Taiwan

The increased incidence of colorectal cancer in women with a history of breast cancer is well established. However, the relationship between the prevalence of adenomatous polyps and breast cancer is still controversial. We conducted a prospective study of the incidence of colorectal polyps in patients with a history of breast cancer in Taiwan. Eighty-nine patients (86 women and 3 men) received colonoscopy to test for precancerous lesions. Mean age was 49.4 +/- 10.4 years. Twelve polyps (9 adenomatous, 2 hyperplastic, 1 inflammatory) (13.5%) and one cancer (1.1%) were found. The mean age of patients with and without colorectal neoplasia was 56.3 +/- 9.4 and 48.2 +/- 10.2 years respectively, (p < 0.005); 10 out of 13 patients (77%) with colorectal neoplasia were over 50 (p < 0.1). Compared with a study of Chinese people in Hong Kong, our population had a lower incidence of colorectal adenomatous polyps, but breast cancer patients have a greater risk of developing colorectal cancer than the general population in Taiwan.

Diagnostic role of endoscopy, stool culture, and toxin A in Clostridium difficile-associated disease

This retrospective study was designed to assess the roles of stool culture for Clostridium difficile, detection of the presence of toxin A, and endoscopic examination in the diagnosis of Clostridium difficile-associated disease (CDAD). From January 1994 through September 1996, there were 213 patients with stool cultures positive for C. difficile in National Taiwan University Hospital. Of these, 126 had CDAD. There were 87 asymptomatic carriers of C. difficile in our study, 12 of whom were positive for toxin A. In addition, seven patients with pseudomembranous colitis (PMC), who were either culture-negative or not tested, were included in the study. The positive predictive values of stool cultures for CDAD and PMC were 59% and 32%, respectively. The positive predictive values of toxin A for CDAD and PMC were 41% and 43%, respectively. Seventy-eight patients (59%) improved with supportive treatment after discontinuing antibiotics. We concluded that stool culture for C. difficile and discontinuation of antibiotics should be the standard approach for patients with suspected CDAD. Endoscopic studies can eliminate some other possible causes of diarrhea such as inflammatory bowel disease, allow biopsies of suspicious lesions, and reveal the severity of CDAD. Toxin assay results need to be interpreted together with the clinical data.

Biodegradable microparticles with an entrapped branched octameric peptide as a controlled-release HIV-1 vaccine

Polyactide-co-glycolide microparticles, with an entrapped branched octameric peptide from human immunodeficiency virus (HIV-1), were prepared by a solvent evaporation method. The microparticles were characterized for size distribution, antigen loading level, and integrity. Mice in one group were each immunized with a single dose of a controlled-release microparticle formulation containing 300 micrograms of peptide and the serum IgG responses to the antigen were compared with those of mice from a second group that were immunized at 0, 4, and 26 weeks with 100-microgram doses of the same peptide immunogen adsorbed to alum. The controlled-release microparticles induced an antibody response comparable to that from the alum-immunized group. The subcutaneous and the intramuscular routes of administration were compared in additional groups of mice for the microparticles, and both routes induced similar responses. A suspending vehicle for the microparticles was also evaluated and did not affect the immunogenicity of the controlled-release formulation containing both small and large microparticles, although the immunogenicity of smaller microparticles immunized alone was affected.

CTL induction using synthetic peptides delivered in emulsions--critical role of the formulation procedure

Emulsions have been used with variable degrees of success to deliver antigen to stimulate immune responses. We have investigated three different ways of incorporating peptide antigen into soybean emulsions to induce CTL responses in mice. Two of these emulsions (oil-in-water, o/w, and water-in-oil-in-water, w/o/w) had peptide incorporated at the formulation stage, while the third had peptide added to a pre-formed o/w emulsion. High levels of CTL activity were induced when peptide was dispersed into the o/w or w/o/w emulsions, in contrast to addition of peptide to the pre-formed o/w emulsion, which did not stimulate a CTL response. Induction of CTL activity was independent of emulsion globule size but was correlated with a negative zeta potential and dispersion of peptide in the oil phase. The ability of peptide in soybean oil emulsion to induce CTL is critically dependent on dispersion of peptide at the time of emulsion formation.

Embryonic stem cell lines from MRL mice allow genetic modification in a murine model of autoimmune disease

The MRL/MpJ-Fas(lpr) (MRL-lpr/lpr) mouse spontaneously develops a generalized autoimmune disease with features similar to those of systemic lupus erythematosus. This mouse strain provides a valuable system for identifying and characterizing the multiple genetic factors that influence the pathogenesis of autoimmune diseases. One of the most powerful means of examining the role of a specific gene product in vivo is by inactivating the gene in mouse embryonic stem (ES) cells by homologous recombination and using these cells to derive mouse lines carrying the inactivated gene. The successful application of this approach, however, requires an ES cell line that will remain stable in culture during the processes of genetic manipulation and selection. To date, ES cell lines that meet this criterion have been derived from only a few mouse strains. Here we describe the production and characterization of stable ES cell lines from the MRL mouse strain. Approximately 7% of the blastocysts derived from the MRL/MpJ+ (MRL-+/+) strain gave rise to ES cell lines, and both of the male MRL-+/+ ES cell lines tested were shown to be germline competent. We show that the MRL-+/+ ES cell lines undergo gene targeting by homologous recombination at high frequency by inactivating the gene encoding the EP2 prostaglandin receptor. These Ep2-targeted MRL ES cell lines were used to generate MRL mouse lines heterozygous for the disrupted Ep2 gene, thus demonstrating the feasibility of using a genetic approach to dissect the pathobiology of the autoimmune disease in the MRL mouse.

Embryonic stem cell lines from MRL mice allow genetic modification in a murine model of autoimmune disease

The MRL/MpJ-Fas(lpr) (MRL-lpr/lpr) mouse spontaneously develops a generalized autoimmune disease with features similar to those of systemic lupus erythematosus. This mouse strain provides a valuable system for identifying and characterizing the multiple genetic factors that influence the pathogenesis of autoimmune diseases. One of the most powerful means of examining the role of a specific gene product in vivo is by inactivating the gene in mouse embryonic stem (ES) cells by homologous recombination and using these cells to derive mouse lines carrying the inactivated gene. The successful application of this approach, however, requires an ES cell line that will remain stable in culture during the processes of genetic manipulation and selection. To date, ES cell lines that meet this criterion have been derived from only a few mouse strains. Here we describe the production and characterization of stable ES cell lines from the MRL mouse strain. Approximately 7% of the blastocysts derived from the MRL/MpJ+ (MRL-+/+) strain gave rise to ES cell lines, and both of the male MRL-+/+ ES cell lines tested were shown to be germline competent. We show that the MRL-+/+ ES cell lines undergo gene targeting by homologous recombination at high frequency by inactivating the gene encoding the EP2 prostaglandin receptor. These Ep2-targeted MRL ES cell lines were used to generate MRL mouse lines heterozygous for the disrupted Ep2 gene, thus demonstrating the feasibility of using a genetic approach to dissect the pathobiology of the autoimmune disease in the MRL mouse.

Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas

BACKGROUND

The histopathologic spectrum of colorectal neuroendocrine tumors ranges from benign to highly malignant. In this spectrum, poorly differentiated neuroendocrine carcinoma (PDNC) is the most aggressive type, characterized by early dissemination and a rapidly fatal course. Since it is unclear whether PDNC originates from neoplastic transformation of preexisting neuroectodermal cells, pluripotent epithelial stem cells, or adenocarcinoma precursor cells, we investigated the histogenesis of this type of cancer by performing genetic analyses on a series of colorectal tumors.

METHODS

Archived histologic sections of colorectal PDNC from nine patients were analyzed; gastrointestinal carcinoid tumor specimens from four patients were used as controls. The specimens were deparaffinized, microdissected, and analyzed genetically. After DNA extraction, polymerase chain reaction amplification was performed to investigate alteration (i.e., loss of heterozygosity [LOH]) of the APC (adenomatous polyposis coli), DCC (deleted in colorectal carcinoma), and p53 (also known as TP53) genes.

RESULTS

LOH of the APC, DCC, or p53 genes was observed in six of eight informative PDNC tumors; no LOH was detected in the carcinoid control specimens. Four of five informative PDNC tumors had associated adenocarcinoma; LOH of the APC and p53 genes in these tumors involved the same allele in both tissue components. Four of the five tumors with associated adenocarcinoma showed LOH of the DCC gene; in three of these four tumors, the PDNC and adenomatous components showed LOH of the same allele.

CONCLUSIONS

PDNC and associated adenocarcinoma appear to be derived from the same cell of origin, which is most likely either a pluripotent epithelial stem cell or an adenocarcinoma precursor cell.

Carcinogenecity of the N-acyl derivatives of N-hydroxy-trans-4-aminostilbene in CD rats

Carcinogenicities of the N-formyl (N-OH-FAS), N-acetyl (N-OH-AAS) and N-propionyl (N-OH-PAS) derivatives of N-hydroxy-trans-4-aminostilbene (N-OH-AS) were investigated in male and female CD rats. They were injected, i.p. 10 mumol/kg body weight (bwt) twice a week for 6 weeks, and they were killed at the end of 62 weeks. The N-formyl, N-acetyl and N-propionyl derivatives of N-hydroxy-4-aminobiphenyl (N-OH-ABP) were similarly injected at a dose of 100 mumol/kg bwt for comparison in female CD rats. Tumors of the liver, mammary gland and ear duct were produced in the female rats by these N-OH-AS derivatives. N-OH-AAS and N-OH-PAS were more active in the induction of mammary and ear duct tumors than N-OH-FAS. These N-OH-AS derivatives produced more tumors than did the N-OH-ABP derivatives, even at 1/10 dose of the N-OH-ABP derivatives. In male CD rats, these N-OH-AS derivatives produced peritesticular mesothelioma and tumors of the pancreas and ear duct. N-OH-PAS also produced tumors of the small intestine and lung. The acetyl and propionyl derivatives were more carcinogenic than the formyl derivative of N-OH-AS for both male and female CD rats, suggesting that cytosolic acetyltransferases may be more important than the microsomal ones in activating these carcinogens.

New developments in the use of cytokines for cancer therapy

Cytokines, the pleiotropic immune regulatory proteins, are involved in the regulation of cell growth, differentiation and functional activation. Novel cytokines have been enumerated in rapid succession and entered the clinical arena. IL-2 is well recognized for its antitumor effects and is accepted therapy for numerous malignancies. IL-l and IL-11 are important as thrombopoetic factors while IL-6 has been introduced in clinical trials as a platelet growth factor and as an antitumor agent. IL-4 has shown growth inhibitory effects against many solid tumor cell lines in vitro, but its direct effect on human tumors in vivo remains to be explored. IL-7 may be an important addition to the current strategies of adoptive immunotherapy. IL-12 plays a fundamental role in activating antitumor cellular immunity. When given with tumor associated antigens, IL-12 has proven effective against many forms of metastatic solid tumors. Immunotoxins appear to be promising, though the antigenicity of the molecule and antibody development aspects remain to be resolved. The current review will focus on the clinical use of novel cytokines for the treatment of cancer.

Synthetic-peptide-based enzyme-linked immunosorbent assay for screening human serum or plasma for antibodies to human immunodeficiency virus type 1 and type 2

A synthetic-peptide-based enzyme-linked immunosorbent assay (EIA) capable of screening for antibodies to both human immunodeficiency virus type 1 (HIV-1) and HIV-2 has been developed for use in blood banks and diagnostic laboratories. Microtiter wells are coated with two synthetic peptides, one corresponding to the highly conserved envelope region of HIV-1 and another corresponding to the conserved envelope region of HIV-2. Overall, sensitivity was 100% in 303 individuals diagnosed with AIDS and 96 individuals diagnosed with AIDS-related complex, 14.8% in a study of 500 high-risk group members, 99.9% in 600 EIA repeatedly reactive (RR)-HIV-1 Western blot (WB)-positive repository specimens, and 100% for 222 geographically diverse HIV-1 specimens and 216 confirmed HIV-2-positive specimens evaluated. The specificity was determined to be 99.72% for a total of 13,004 serum and plasma samples from random volunteer donors evaluated across five blood banks. Forty donors who were found to be EIA RR-WB indeterminate but nonreactive on the United Biomedical, Inc., test (UBI HIV 1/2 EIA) were prospectively followed as an additional measure of specificity. None of the 40 low-risk cases evolved into a positive WB pattern at follow-up. The sensitivity and specificity of this new assay are comparable to those of other Food and Drug Administration-licensed HIV-1 and HIV-1-HIV-2 assays that are currently available in the United States. The UBI HIV 1/2 EIA affords laboratories another choice in the detection of antibodies for HIV-1 and HIV-2 with a test based on an alternative antigen format.

Interleukin-13 receptors on human prostate carcinoma cell lines represent a novel target for a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin

We have discovered a new cell surface protein in the form of interleukin-13 receptor on several solid tumor cells, including human renal cell carcinoma cells (Obiri et al., 1995; Debinski et al., 1995). This study reports that human prostate cancer cell lines also express high affinity IL-13 receptors (Kd = 159 pM). These receptors are functional because IL-13 surprisingly increased proliferation of all three prostate cancer cell lines studied as determined by thymidine uptake and clonogenic assays. IL-13 receptors on prostate cancer cell lines were targeted using a chimeric protein composed of IL-13 and a mutated form of Pseudomonas exotoxin (PE38QQR). This molecule, termed IL13-PE38QQR, has been found cytotoxic to all three prostate cancer cell lines as determined by the inhibition of protein synthesis. The IC50 ranged between 1 nmol/l, to 15 nmol/l. These data were confirmed by clonogenic assays in which IL13-PE38QQR almost completely inhibited colony formation at 10 nmol/l. IL13-PE38QQR was not cytotoxic to cells that express little or no IL-13R. Heat inactivated IL13-PE38QQR was not cytotoxic to prostate cancer cells indicating specificity. IL13-PE38QQR was also cytotoxic to colonies when they were allowed to form first for several days before the addition of toxins. Our data suggest that additional studies should be performed to target IL-13 receptor bearing prostate cancer.

Increased susceptibility of RAG-2 SCID mice to dissemination of endodontic infections

Specific immunity has been implicated in the pathogenesis of periapical lesions, although the extent to which these mechanisms are actually involved in either protection or destruction of the pulp-periapex complex is yet to be established. To investigate this question we compared periapical-lesion pathogenesis in RAG-2 severe combined immunodeficient (SCID) mice with immunocompetent control mice following surgical pulp exposure. In order to equalize the bacterial challenge, an infection protocol using Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros, and Streptococcus intermedius was devised. The results demonstrated that after infection, the proportion of the root canal flora represented by the four pathogens was almost identical in both groups (39.9 and 42.2% for RAG-2 and immunocompetent control mice, respectively). The effects of abrogation of T- and B-cell mechanisms on periapical pathogenesis were then assessed. Approximately one-third of the RAG-2 mice developed endodontic abscesses, while no immunocompetent controls had abscesses, results which indicated regional dissemination of the infection. A similar incidence of abscesses was found in two additional experiments. Abscessed RAG-2 teeth had significantly larger periapical lesions than did nonabscessed RAG-2 teeth (P < or = 0.05) and exposed immunocompetent controls (P < or = 0.01), whereas nonabscessed RAG-2 teeth were not significantly different from those of exposed immunocompetent controls in periapical-lesion size. We conclude that B- and T-cell-mediated immunity protects the host from the dissemination of endodontic infections and that RAG-2 mice are more susceptible to infection-induced pulp-periapex destruction.

The cross-cultural applicability of Orem's conceptual framework

This study examined the applicability of the Orem's Theory of Self-Care with Chinese clients. The central concepts included the universal self-care behaviors (USC), health-deviation self-care behaviors (HDSC), health, and the basic conditioning factors of adults with Type II diabetes mellitus. Basic conditioning factors (BCF) were internal or external factors that affected an individual's ability to engage in self-care bahaviors (Orem, 1991). This study used a descriptive correlation design. Orem's theory of self-care guided the selection of the variables and the hypothesized outcomes. Data were collected through phone interviews of 100 Chinese at Taiwan. The average age was 57.88 (SD = 12.41). A total of 51 items on questionnaires was used to measure self-care behaviors and health. An investigator developed a questionnaire assessing sociodemographic characteristics. Sixty-six percent of respondents perceived they lived with someone who helped too much and hindered their own diabetes-related self-care. A significant correlation was found between educational level and diabetes-related self-care behaviors. A significant correlation was also found between the educational level and the universal self-care behaviors. There were significant correlations among the universal self-care behaviors and diabetes-related self-care; between the universal self-care behaviors and the perception of health; between the diabetes-related self-care behaviors and the perception of health. The findings implicated cross-cultural applicability of Orem's conceptual framework.

Adaptive control of arterial blood pressure with a learning controller based on multilayer neural networks

We discuss a two-model multilayer neural network controller for adaptive control of mean arterial blood pressure (MABP) using sodium nitroprusside. A model with an autoregressive moving average (ARMA), representing the dynamics of the system, and a modified back-propagation training algorithm are used to design the control system to meet specified objectives of design (settling time and undershoot/overshoot) and clinical constraints. The controller is associated with a weighting-determinant unit (WDU) to determine and update the output weighting factor of the parallel two-model neural network for adequate control action and a control-signal modification unit (CMU) to comply with clinical constraints and to suppress the effect of adverse noise and to improve the WDU performance. Extensive computer simulations indicate satisfactory performance and robustness of the proposed controller in the presence of much noise, over the full range of plant parameters, uncertainties, and large variations of parameters.

Comparative pathology of benign prostatic hyperplasia and prostate cancer

Basic studies on the pathogenesis of prostate disease including hypertrophy and cancer have been difficult due to the lack of suitable animal models. Much effort has been directed to the development of appropriate animal models, and yet many obstacles still remain. Rodents do not develop spontaneous hypertrophy of the prostate, in fact the prostate atrophies with advancing age. Guinea pigs appear to be a good model to study the effect of hormones on the prostate gland. Microinvasive prostatic adenocarcinoma occurs spontaneously in various species of rodents, and can be induced by radiation, hormones and chemical carcinogens. The man and dog appear to be the only mammals which suffer naturally from the pathological processes of the prostate gland associated with aging. We review the currently available models for the study of benign, and malignant prostate disease and assess the strengths and weaknesses each for preclinical investigations.

A model for osseous metastasis of human breast cancer established by intrafemur injection of the MDA-MB-435 cells in nude mice

BACKGROUND

A nude mouse model was developed and studied for temporal pathogenesis of bony metastasis of human breast cancer.

MATERIALS AND METHODS

Human breast cancer cells, MDA-MB-435, were injected into the medulla of left femurs of 10 Beige nude mice, whereas their right femurs were similarly injected with phosphate buffered saline as a control. The mice were killed at 1 week-intervals for up to 5 weeks.

RESULTS

Tumors appeared in all the animals 3 weeks after the injection: they began to appear in the medulla at 2 weeks, and invasion of the tumor into the cortex and surrounding tissues of the bone appeared at 4 weeks. Both osteolytic and osteoblastic activation frequently observed in the affected bone of breast cancer patients were present.

CONCLUSION

This model produces a high incidence of bony metastasis and may be appropriate for the study of osseous metastasis of this human disease.

Identification of a second endogenous Porphyromonas gingivalis insertion element

In this study a second endogenous Porphyromonas gingivalis insertion element (IS element) that is capable of transposition within P. gingivalis was identified. Nucleotide sequence analysis of the Tn4351 insertion site in a P. gingivalis Tn4351-generated transconjugant showed that a complete copy of the previously unidentified IS element, designated PGIS2, had inserted into IS4351R in Tn4351. PGIS2 is 1,207 bp in length with 19-bp imperfect terminal inverted repeats, and insertion resulted in a duplicated 10-bp target sequence. Results of Southern hybridization of chromosomal DNA isolated from several P. gingivalis strains with a PGIS2-specific probe demonstrated that the number of copies of PGIS2 per genome varies among different P. gingivalis strains. Computer analysis of the putative polypeptide encoded by PGIS2 revealed strong homologies to the products encoded by IS1358 from Vibrio cholerae, ISAS1 from Aeromonas salmonicida, and H-rpt in Escherichia coli K-12.

Reflux esophagitis after proximal subtotal gastrectomy

BACKGROUND

Carcinoma of the cardia of stomach or carcinoma of the esophagocardiac (EC) junction has a poor prognosis. Proximal subtotal gastrectomy is often performed for a smaller tumor. It achieves a prognosis similar to that of total gastrectomy and prevents pernicious anemia. A better functional result was expected than that total gastrectomy did from us, but the clinical observation was surprising. Most patients had symptoms of reflux esophagitis after surgery. All of these patients were reevaluated.

METHODS

From November, 1990 to March, 1996, there were 27 patients who received proximal subtotal gastrectomy at this hospital. Twenty of these were involved in this study. Floppy Nissen's fundoplication was performed during operation as a anti-reflux procedure. Continuous 24-h pH monitoring, esophageal manometry, and endoscopic examination were performed for study.

RESULTS

Most of the patients had symptoms of gastroesophageal reflux. 80% (16/20) of the patients were found to have reflux esophagitis under endoscopy. The patients had higher pH scores (mean 85.8 +/- 45.6) than normal (< 17.5), lower pressure of LES (8.03 +/- 7.01 mmHg), shorter total lengths (mean 1.60 +/- 0.56 cm) and intraabdominal lengths (mean 1.29 +/- 0.30 cm) of new lower esophageal sphincters.

CONCLUSIONS

Clearly there was failure to prevent reflux esophagitis through floppy Nissen's fundoplication. Severe gastroesophageal reflux did appear after proximal gastric resection. A gastric remnant with safe cut-margin is often too short to perform complete wrapping. Proximal subtotal gastrectomy is not recommended for early cancer of the cardia of the stomach.

Homozygosity and linkage-disequilibrium mapping of the urofacial (Ochoa) syndrome gene to a 1-cM interval on chromosome 10q23-q24

The urofacial (Ochoa) syndrome (UFS) is a rare autosomal recessive disease characterized by congenital obstructive uropathy and abnormal facial expression. The patients present with enuresis, urinary-tract infection, hydronephrosis, and voiding dysfunctions as a result of neurogenic bladders. To map the UFS gene, a genome screen using a combination of homozygosity-mapping and DNA-pooling strategies was performed in 20 selected patients, one patient pool, and three control pools (unaffected relatives). After analyses of 36 randomly chosen markers, D10S677 was identified as being linked to and associated with UFS, as suggested by a significant excess of homozygosity in patients compared with that in unaffected relatives (P < 10(-6)), as well as by the allelic-frequency differences between the patient pool and control pools. Ten additional markers flanking D10S677 and covering a 22-cM region then were analyzed to fine-map the UFS gene by use of haplotype (linkage disequilibrium) analysis. All 31 patients were found to be homozygous for two closely linked markers (D10S1726 and D10S198) located approximately 5 cM telomeric to D10S677, whereas only 12% of the unaffected relatives were homozygous for both markers (P < 10(-19)). Several patients are heterozygous at two markers immediately flanking D10S1726/D10S198, one on the centromeric side (D10S1433) and the other on the telomeric side (D10S603). These recombinational events place the UFS gene near D10S1726/D10S198 and within a 1-cM interval defined by D10S1433 and D10S603 on chromosome 10q23-q24.