Gastric intestinal metaplasia in ethnic groups in the southwestern United States

The incidence of gastric cancer has declined dramatically in the United States during this century. However, the incidence of gastric cancer among Hispanics, Blacks, and Native Americans remains 2-3-fold higher than among Whites in this country. Populations with an increased risk of gastric cancer have predominantly the "intestinal" type of gastric cancer, and intestinal metaplasia is regarded as a histological precursor lesion of this type of gastric cancer. We sought to establish the prevalence of intestinal metaplasia, identify associated epidemiological factors, and improve detection of this lesion in a patient population undergoing clinically indicated endoscopy in the Southwestern United States. Among the 440 patients studied, we observed an overall crude prevalence of intestinal metaplasia of 19%. However, the crude prevalence among Hispanics and Blacks was found to be markedly higher than among non-Hispanic Whites (50% versus 13%). Two biopsy protocols (two biopsies versus four biopsies) were used during this study, with a significantly higher rate of intestinal metaplasia detection under the four-biopsy protocol. Adjusting for protocol, we found that age and ethnicity were significantly and independently associated with the prevalence of intestinal metaplasia. The odds of intestinal metaplasia diagnosis was significantly higher in Hispanics compared to non-Hispanic Whites (P < 0.001), and the prevalence of intestinal metaplasia increased with advancing age (P = 0.01). The presence of Helicobacter pylori was also significantly associated with the presence of intestinal metaplasia (P = 0.02), although the direction of the association differed between Hispanics and non-Hispanic Whites.

Tissue culture of epithelial cells from esophageal specialized columnar epithelium (Barrett's esophagus)

A procedure is described for the tissue culture of epithelial cells from Barrett's specialized columnar epithelium. The method employs use of nonenzymatic disaggregation techniques and use of a specialized growth medium, M-19. Successful growth can be achieved in 60-70% of cases. Characteristics of four cultures are presented including PAS, Alcian blue, and cytokeratin staining properties. Ultrastructural studies showed the presence of distended rough endoplasmic reticulum, abundant Golgi apparatus, glycogen granules, and cell-cell junctional complexes. Colony formation in anchorage-independent growth in soft agar was not observed in any culture. The cultured cells were not capable of indefinite growth. Thus, they do not behave as fully transformed cells. Availability of this culture system should be of use to the study of the biology of this metaplastic premalignant lesion.

A Preliminary Trial of Beta-Carotene in Subjects Infected with the Human Immunodeficiency Virus

beta-Carotene is a nontoxic carotenoid with immunomodulating properties in animals and humans. Based on our observations in normal immunocompetent subjects, we studied the effects of this compound in 11 patients infected with the human immunodeficiency virus (HIV). Each subject received 60 mg of beta-carotene daily for 4 mo. Clinical and laboratory studies were obtained at baseline, every month while on treatment and for 2 mo after treatment. Increases in the percent of cells expressing Leu 11 (natural killer cells), Ia antigen and transferrin receptor (activated lymphocytes) were observed after 3 mo of treatment with beta-carotene and diminished thereafter. Major changes were not seen in total lymphocyte count or in the percent of cells expressing CD11, CD8 or CD4 antigens. No clinical toxicity was observed. These data suggest that beta-carotene can modulate certain immune markers in HIV-infected subjects. Further study of this compound in HIV infection may be warranted.

Measures of tumor proliferative activity

Tumor proliferative activity, or labeling index, is of interest for gaining insight into the biologic properties of human neoplasm and for providing clinical information that might guide patient management. There has been an abundance of literature reporting experience with standard and newer techniques of measuring tumor proliferative activity. These methods are reviewed with emphasis on technical issues. Particular attention is paid to the development and use of monoclonal antibodies, Ki-67 and anti-PCNA/cyclin. These antibodies are readily available and relatively simple to use. The former has recently been shown to be of prognostic value in non-Hodgkin's large cell lymphomas. A number of studies suggest that indices using these techniques could be useful for a variety of carcinomas, soft tissue tumors, and tumors of the central nervous system.

Effectiveness of India ink as a long-term colonic mucosal marker

We prospectively studied the use of India ink as a long-term or "permanent" mucosal marker as part of a study investigating the natural history of diminutive distal colorectal polyps. Twenty-six patients had 32 India ink tatoos implanted. The tatoo sites of the 19 patients who were followed at least 6 months continued to display intensely stained mucosa at the original sites. No side effects or complications were encountered. India ink appears to be a safe and effective long-term marker for colonic mucosal lesions.

Polyamine contents in rectal and buccal mucosae in humans treated with oral difluoromethylornithine

Difluoromethylornithine (DFMO) is an investigational chemopreventive agent that inhibits ornithine decarboxylase (ODC) activity, lowers cellular polyamine concentrations, and decreases cell proliferation in vivo and in vitro. In five subjects we have compared the polyamine concentrations in rectal mucosal biopsies and in exfoliated buccal mucosal cells (EBM) before and after DFMO treatment to assess the suitability of EBM as an easily accessible marker tissue for DFMO suppression of polyamine synthesis in the rectal mucosa. One month of 3 g/m2/day of DFMO treatment caused a statistically significant decrease in putrescine and spermidine concentrations in rectal mucosa biopsy specimens but not in EBM samples. ODC activity in EBM was high (approximately 1 mumol/min/mg protein), resistant to DFMO inhibition (Ki = 4200 microM), dependent on GTP concentration (maximal at 0.1 mM), and was reduced concomitantly with bacterial concentration by antiseptic mouthwashing. Bacteria adherent to EBM were visible by electron microscopy. Forty bacterial colonies/ng protein were culturable from washed EBM samples. Oral bacteria preclude the use of EBM samples as a marker tissue of DFMO effect in the rectal mucosa, but oral DFMO therapy is effective in depleting polyamines in rectal mucosa.

A phase II study of chemotherapy of metastatic colorectal carcinoma with 5-fluorouracil plus cisplatin. A Southwest Oncology Group study

The combination of 5-fluorouracil and cisplatin has shown encouraging results in single institution pilot studies in colorectal carcinoma. This phase II SWOG study was undertaken to further evaluate this treatment. Cisplatin was administered at a dose of 60 mg/M2 IV day 1, repeated every 21 days. 5-FU was given at a dose of 15 mg/Kg IV days 1, 8, and 15, with cycles repeated every 21 days. Among 47 eligible patients there were no complete responses and only three partial responses for an overall response rate of 6% with a 95% confidence interval of 1% to 18%. Seventeen patients (36%) had stable disease/no response and 22 (47%) progressed. Five patients (10%) had no evaluation and were assumed to have had no response, or were early deaths. Median survival was 9.1 months. Significant hematologic toxicity was seen with grade 3 leukopenia occurring in 11 patients. There were felt to be two deaths definitely related to treatment and two additional deaths possibly treatment related. The combination of 5-FU and cisplatin used in this dose and schedule is an ineffective and toxic regimen for treatment of colorectal carcinoma.

The effects of 13-cis-retinoic acid and beta-carotene on cellular immunity in humans

Deficiency of vitamin A and/or its precursors has been associated with increased cancer risk in animals and humans. Therapeutic trials of vitamin A and related compounds have demonstrated activity in several cancerous and precancerous conditions. The authors measured the effects of a retinoid, 13-cis-retinoic acid, and a carotenoid, beta-carotene, on the human immune system in vivo in conjunction with their use in ongoing clinical trials. Immune cell subpopulations were analyzed by quantifying the expression of markers using flow cytometric study. Both compounds produced significant effects on immune cell populations. 13-cis-Retinoic acid resulted in an increase in the percentage of peripheral blood lymphoid cells expressing surface markers for T-helper cells with only minimal effect on natural killer cell marker expression. In contrast, beta-carotene produced an increase in the percentage of cells expressing natural killer cell markers with smaller effect on T-helper markers. Modest increases in the percentage of cells expressing Ia antigen, transferrin, and interleukin-2 receptors were produced by both drugs. These results suggest that retinoids and carotenoids can produce major changes in immune cellular marker expression in vivo in humans at doses relevant to their potential clinical use.

Prospective blinded trial of the colonoscopic miss-rate of large colorectal polyps

We prospectively studied the colonoscopic miss-rate of large colorectal polyps in a blinded trial featuring tandem colonoscopy. Sixty-three lesions greater than or equal to 1 cm in size were discovered and none were missed. Confidence intervals of 95% are a miss-rate of 0 to 4.6%. We conclude that less than 5% of large colorectal polyps are missed during the index colonoscopic examination in a well-prepared colon.

Chemoprevention of cancer

Chemoprevention is a relatively new area of clinical cancer research. In this article we have presented a general overview of the concepts as well as the status of ongoing clinical trials using the most promising agents in selected populations. The reader is referred to recent excellent reviews presenting more detailed discussions of the various topics discussed, such as the selection process for new agents, in vitro and animal model screening procedures, epidemiologic studies, and other agents now being screened and tested for potential clinical study. Increased understanding of the biology of carcinogenesis will undoubtedly lead to new ideas and approaches. Pathways for conversion of proto-oncogenes to tumor-supporting oncogenes, the mechanisms of action of tumor suppressor genes, and the involvement of abnormal growth factor responses in producing "field cancerization" are some examples of future targets for chemopreventive intervention. Long-term goals of this effort will include application of the results of early promising prevention studies, such as those in oral premalignant lesions, to the design of carefully controlled trials to demonstrate actual inhibition of cancer occurrence. In the laboratory, basic studies need to be conducted to increase our understanding of the molecular events underlying carcinogenesis, in order to identify additional targets for new agents to enhance the clinical efforts. Some of the most exciting developments in the control of cancer over the next decade will very likely result from this chemopreventive approach, with application not only to prevention of the first or primary malignancy, especially in high risk populations, but also to clinical situations traditionally considered to be in the domain of chemotherapeutic strategies, such as adjuvant treatment after definitive therapy of a primary cancer.

Potential role of beta-carotene in prevention of oral cancer

Recent data suggests that retinoids and carotenoids may be effective in reversing a putative "field cancerization" defect in the epithelium at risk for oral cancer. Animal experiments have shown that these compounds can inhibit cancer formation. Several clinical trials have demonstrated the ability of retinoids to reverse oral leukoplakia. However, toxicities associated with retinoids at the doses used in these studies limits their potential for chemoprevention. Because of its lack of toxicity, beta-carotene is a very attractive agent for chemoprevention. It suppresses micronuclei in exfoliated oral mucosal cells from subjects at risk for oral cancer and recently has been shown to be active in reversing leukoplakia. Another area under investigation is the possibility of preventing second primary tumors in patients cured of their initial cancer who have an increased risk of developing new cancers of the upper acrodigestive tract.

Depletion of myocardial adenosine triphosphate during prolonged untreated ventricular fibrillation: effect on defibrillation success

We studied left ventricular endomyocardial adenosine triphosphate levels in 13 large mongrel dogs before and during ventricular fibrillation induced cardiac arrest to assess whether myocardial adenosine triphosphate content could predict successful cardiopulmonary resuscitation. Endomyocardial biopsies were performed during sinus rhythm (control), after 15 min of ventricular fibrillation or 10 min of ventricular fibrillation and 5 min of open chest cardiopulmonary resuscitation, after 20 min of ventricular fibrillation and 10 min of open chest cardiopulmonary resuscitation and after 40 min ventricular fibrillation and 15-20 min open chest cardiopulmonary resuscitation. Myocardial adenosine triphosphate was measured utilizing a bioluminescence method adapted for use with endomyocardial biopsies and normalized to protein content. Left ventricular endomyocardial adenosine triphosphate content fell significantly over time from a control level of 8.88 +/- 0.9 micrograms/mg protein to 5.73 +/- 0.5 micrograms/mg protein at 15 min of cardiac arrest, to 3.4 +/- 0.4 micrograms/mg protein after 30 min of cardiac arrest and to 1.98 +/- 0.3 micrograms/mg protein after 60 min of cardiac arrest (P less than 0.001). Adenosine triphosphate levels were significantly different between animals that received 10 min of ventricular fibrillation and successful open chest cardiopulmonary resuscitation and those that received 40 min of ventricular fibrillation and unsuccessful open chest cardiopulmonary resuscitation (4.35 +/- 0.48 vs. 2.11 +/- 0.43 micrograms/mg protein; P less than 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Persistent rectal ulcer associated with human papillomavirus type 33 in a patient with AIDS: successful treatment with isotretinoin

Rectal dysplasia and carcinoma associated with human papillomavirus infection are increasing in prevalence among homosexual men, particularly those infected with the human immunodeficiency virus. We report a case involving a 39-year-old homosexual man with AIDS who developed a persistent rectal ulcer. A biopsy of the ulcer revealed severe squamous dysplasia, and human papillomavirus type 33 was detected in rectal tissue with use of in situ DNA hybridization. This genotype of virus has not been previously associated with anal or rectal dysplasia in homosexual men, including those infected with the human immunodeficiency virus. The rectal ulcer resolved after 2 months of oral therapy with 60 mg/d of isotretinoin, a retinoid.

Response of oral leukoplakia to beta-carotene

Leukoplakia is associated with increased risk of oral cancer and is considered a premalignant lesion. Retinoids, particularly 13-cis retinoic acid, can frequently reverse leukoplakia. However, these drugs have considerable toxicity and are not suitable for large-scale use in the prevention of oral cancer. Beta-carotene is a naturally occurring, nontoxic carotenoid with biologic properties that suggest that it might be efficacious against oral leukoplakia. In 1986, we began a randomized study of 13-cis retinoic acid (1 mg/kg/d) versus beta-carotene (30 mg/d) in leukoplakia. However, owing to the marked differences in toxicity between the two compounds outlined in the consent form, 11 of the initial 16 eligible patients refused to participate unless they were "guaranteed" beta-carotene. Therefore, the study design was changed to a phase II trial of beta-carotene in which the compound was given daily for 3 months. Responding patients were continued for another 3 months of treatment. All lesions were examined histologically at entry. Responses were monitored by bidimensional measurements and photography done at entry, then monthly while on treatment and at study completion. Twenty-four evaluable patients were treated, and 17 had major responses (two complete, 15 partial), a response rate of 71% (95% confidence limits, 53% to 89%). There was no significant toxicity requiring drug discontinuation or dose reduction. These results indicate that beta-carotene has substantial activity in oral premalignancy. Because of its lack of toxicity, it is an excellent candidate for a preventive agent for oral cancer.

The myelodysplastic syndromes: biology and implications for management

Since the initial efforts to characterize the myelodysplastic syndromes in 1976, an extensive body of information has accumulated defining biologic features and the relation to clinical aspects of disease. While the pathogenesis of these disorders remains incompletely understood, laboratory investigations indicate that they are clonal disorders affecting hematopoietic stem cells characterized by a progressive imbalance between self-renewal and differentiation. Despite karyotypic resemblance to acute myeloid leukemia, fundamental biologic differences may underly the disappointing results achieved to date with intensive chemotherapy. The recent availability of recombinant hematopoietic growth factors for use in clinical trials has shown that the maturation defect in many instances can be overcome with administration of lineage-restricted recombinant hematopoietins. Routine use of these promising agents must await results of randomized clinical trials to determine the impact of prolonged treatment on leukemic evolution and disease-related morbidity.

Ki-67 labeling index is a more reliable measure of solid tumor proliferative activity than tritiated thymidine labeling

The proliferative activity of tumors has been shown to have prognostic significance in a variety of solid tumors. The standard method for assessing the proliferating fraction has been the measurement of the tritiated thymidine labeling index (TLI). Ki-67 is a monoclonal antibody that labels proliferating cells. In this study, the authors compared the proliferative activity of seven solid tumor specimens, using both methods simultaneously, on comparable sections from the same specimen. As expected, in every case the Ki-67 labeling index (KiLI) was greater than the TLI. The mean TLI ranged from 4.4 +/- 0.4% to 16.7 +/- 10.2%. The KiLI from these same tumors ranged from 25.7 +/- 8.6% to 41.2 +/- 12.2%. The mean coefficient of variation for measurements from different sections within the same specimen was 28.8 for TLI and 16.4 for KiLI. Therefore, KiLI shows less variability within different sections of the same specimen and is, therefore, a more reliable marker for proliferative activity than is TLI.

Lack of impact of therapy on extent of Barrett's esophagus in 67 patients

Sixty-seven patients with Barrett's esophagus have been prospectively followed over an average of 36 months (range 6 to 76 months) with standardized endoscopic observation and biopsies of the length of columnar epithelium. The initial length of Barrett's epithelium ranged from 1 to 16 cm, mean 5.5 cm. Specialized columnar epithelium was present in 64 of the 67 patients. Patients were treated predominantly with H2-receptor blocker therapy to relieve symptoms. Eighty-two percent of patients had less than a 1-cm change in length per year. The mean rate of change of length was -0.093 cm per year. These results confirm in a relatively large, prospective study that standard antireflux therapy for Barrett's esophagus does not result in consistent reduction in the extent of Barrett's epithelium over a three-year interval.

Chromosomal rearrangements in Barrett's esophagus. A premalignant lesion of esophageal adenocarcinoma

Cytogenetic analysis of 15 short-term cultures of Barrett's esophagus were investigated. In five cases, the number of metaphases identified were insufficient for analysis. Of the remaining ten cases, nine contained clonal chromosome abnormalities. Of these nine cases, one demonstrated a structural chromosome rearrangement, t(3;6)(q21;p23); one case demonstrated trisomy for chromosomes 5 and 7; and seven cases demonstrated loss of the Y chromosome as a clonal change. Our results demonstrate that Barrett's esophagus is frequently characterized by clonal proliferation of karyotypically abnormal cells.

Discordance between flow cytometric abnormalities and dysplasia in Barrett's esophagus

Eighty-six specimens from 25 patients with Barrett's epithelium were analyzed by both histology and flow cytometry. Of these, 73 were without dysplasia and 13 had dysplasia (7 low grade, 6 high grade). Eight of the nondysplastic specimens were aneuploid and another 15 had increased G2. Among the dysplastic specimens, two were aneuploid and two had increased G2. These data were grouped into four classifications: type 1 (65 specimens), specialized columnar epithelium (Barrett's) without dysplasia and no aneuploidy; type 2 (8 specimens), Barrett's epithelium without dysplasia and an aneuploid cell population; type 3 (11 specimens), Barrett's epithelium with dysplasia and no aneuploidy; and type 4 (2 specimens), Barrett's epithelium with dysplasia and aneuploidy. Distribution by type was 76%, 9%, 13%, and 2%, respectively. We conclude that histologic dysplasia and aneuploidy are often discordant. They may identify separate subgroups at risk, or when concordant, may reflect an increased cancer risk in that population. Further study will define the role of histology and flow cytometry in the screening and management of patients with Barrett's esophagus.