Frequent salad vegetable consumption is associated with a reduction in the risk of diabetes mellitus

This cross-sectional study was undertaken to investigate the association between the reported frequency of consumption of vegetables and fruits, the choice of staple carbohydrate, and glucose intolerance. One thousand one hundred twenty-two subjects aged 40-64 years in a population-based study underwent an oral glucose tolerance test, and their food consumption was assessed using a food-frequency questionnaire. The crude prevalence of undiagnosed non-insulin-dependent diabetes mellitus (NIDDM) was 4.5%, and that of impaired glucose tolerance (IGT) 16.8%. The age-standardized prevalence rates were 2.3 and 11.2%, respectively. Frequent consumption of vegetables throughout the year was inversely associated with the risk of having NIDDM (odds ratio [OR] = 0.16; 95% confidence interval [CI] = 0.04-0.69). This association was maintained after adjustment for age, gender, and family history. Vegetable consumption during the summer months had a much weaker inverse association with the risk of having NIDDM that failed to reach statistical significance. A nonsignificant inverse association between frequent consumption of fruits and NIDDM was observed. Frequent self-reported pasta and rice consumption was associated with a reduction in the risk of having IGT and NIDDM. (OR = 0.62, 95% CI = 0.44-0.87, and OR = 0.51, 95% CI = 0.27-0.99, respectively) but this relationship was not independent of age. Whether these associations reflect specific effects of particular nutrients or are a reflection of the patterning of lifestyle factors remains to be determined.

Potency of dietary indole-3-carbinol as a promoter of aflatoxin B1-initiated hepatocarcinogenesis: results from a 9000 animal tumor study

Indole-3-carbinol (I3C), a metabolite of glucobrassicin found in cruciferous vegetables, is documented as acting as a modulator of carcinogenesis and, depending on timing and dose of administration, it may promote hepatocarcinogenesis in some animal models. In this study we demonstrate that, when given post-initiation, dietary I3C promotes aflatoxin B1 (AFB1)-induced hepatocarcinogenesis in the rainbow trout model at levels as low as 500 p.p.m. Trout embryos (approximately 9000) were initiated with 0, 25, 50, 100, 175 or 250 p.p.b. AFB1 by a 30 min immersion. Experimental diets containing 0, 250, 500, 750, 1000 or 1250 p.p.m. I3C were administered starting at 3 months and fish were sampled for liver tumors at 11-13 months. Promotion at the level of tumor incidence was statistically significant for all dietary levels, except 250 p.p.m. Relative potency for promotion markedly increased at dietary levels >750 p.p.m. We propose that more than one mechanism could be involved in promotion and that both estrogenic and Ah receptor-mediated pathways could be active. The estrogenicity of I3C, measured as its ability to induce vitellogenin (an estrogen biomarker in oviparous vertebrates) was evident at the lowest dietary level (250 p.p.m.), whereas CYPIA (a P450 isozyme induced through the Ah receptor pathway) was not induced until dietary levels of 1000 p.p.m. Therefore, at lower dietary levels, promotion by I3C in this model could be explained by estrogenic activities of I3C acid derivatives, as it is known that estrogens promote hepatocarcinogenesis in trout. Much stronger promotion was observed at high dietary I3C levels (1000 and 1250 p.p.m.), at which levels both CYP1A and vitellogenin were induced.

Gastric accommodation in non-ulcer dyspepsia and the roles of Helicobacter pylori infection and vagal function

BACKGROUND

The pathophysiological mechanisms in non-ulcer dyspepsia are incompletely understood.

AIMS

To compare gastric motor and sensory functions in Helicobacter pylori positive or negative patients with non-ulcer dyspepsia.

PATIENTS

Seventeen patients with non-ulcer dyspepsia and 16 asymptomatic controls.

METHODS

The following were evaluated: gastrointestinal symptoms; gastric emptying and orocaecal transit of solids; abdominal vagal function; gastric compliance; fasting and postprandial gastric tone and phasic contractions; symptoms during ingestion of cold water and during the distension of an intragastric bag; and somatic sensitivity and personality profile (Minnesota Multiphasic Personality Inventory, MMPI).

RESULTS

Gastric accommodation was reduced in H pylori negative dyspeptics relative to controls; the degree of accommodation was unrelated to H pylori status in dyspeptics. Increased postprandial gastric sensation was more frequent among H pylori positive patients (4/5 H pylori positive versus 4/12 H pylori negative patients). Intragastric meal distribution and orocaecal transit were normal; gastric emptying at four hours was abnormal in 4/17 patients. Vagal dysfunction was rare. Eight of 17 patients had somatisation or depression on MMPI.

CONCLUSION

Impaired gastric accommodation is frequent in non-ulcer dyspepsia and seems to be unrelated to vagal efferent dysfunction. H pylori infection does not seem to influence gastric accommodation, but is associated with heightened sensitivity in dyspeptics. Therapeutic approaches that restore normal postprandial accommodation and gastric sensitivity should be tested in non-ulcer dyspepsia.

Gastric mechanosensory and lower esophageal sphincter function in rumination syndrome

Our hypothesis was that rumination syndrome is associated with gastric sensory and motor dysfunction. We studied gastric and somatic sensitivity, reflex relaxation of the lower esophageal sphincter (LES), and gastric compliance and accommodation postprandially and postglucagon. A barostatically controlled gastric bag and esophageal manometry were used to compare gastric sensorimotor functions and LES relaxation to gastric distension in 12 patients with rumination syndrome and 12 controls. During bag distensions, patients had greater nausea, bloating, and aggregate score, but not pain, compared with controls (P < 0.05). At 4 and 8 mmHg gastric distension, LES tone reduction was greater in patients than in controls (P < 0.05). Gastric compliance, accommodation to a standard meal, and response to glucagon were not different in patients and controls; however, 6 of 12 patients had no gastric accommodation; the latter patients had significantly greater pain perception during distension (P < 0.05) but normal somatic sensitivity compared with healthy controls. Rumination syndrome is characterized by higher gastric sensitivity and LES relaxation during gastric distension. A subgroup of patients also had absent postprandial accommodation.

Extraction, quantification, and biological availability of fumonisin B1 incorporated into the Oregon test diet and fed to rainbow trout

The purpose of this study was (i) to determine whether pure fumonisin B1 could be incorporated into, recovered, and detected by high-pressure liquid chromatographic analysis from the semipurified Oregon test diet (OTD) used in rainbow trout feeding studies, and (ii) to determine if the incorporated fumonisin B1 was biologically available using the change in free sphingoid bases in liver, kidney, and serum as a mechanism-based biomarker. The results indicate that fumonisin is not easily quantified in the OTD. Recoveries ranged from 12 to 81% of the calculated concentrations based on the fumonisin B1 added to the OTD. However, the fumonisin B1 in the OTD was readily absorbed and biologically active as evidenced by marked increases in free sphinganine in liver, kidney, and serum. The magnitude of the increase in free sphinganine at 100 ppm in the OTD was comparable to that known to be associated with liver toxicity in rats, pigs, and ponies.

A high prevalence of hypertension in rural Sierra Leone

A cross sectional survey to determine the mean systolic and diastolic blood pressure, prevalence of hypertension, and possible risk factors in two villages, Kychum and Njala Komboya, in Sierra Leone was carried out. A total of 463 subjects were investigated. Hypertension was defined according to WHO criteria, i.e. a systolic pressure equal or greater than 160 mmHg, and/or diastolic equal or greater than 95 mmHg. The mean systolic blood pressure for the total population was 131.39 +/- 26.85 mmHg and the mean diastolic blood pressure was 82 +/- 14.80 mmHg. There was no significant difference in blood pressure levels between the two villages. The mean prevalence of hypertension was 22.4%, with Kychum 17.6%, and Njala Komboya 24.8% (X2 = 1.11, p > 0.05). Systolic and diastolic blood pressure levels were associated with age, snuff, (ground tobacco), smoking tobacco leaf, kolanut consumption and parity, but all these associations disappeared when the sample was controlled for age. Age was therefore the most significant correlate of blood pressure. Blood pressure levels were not related to gender, body mass index or cigarette smoking. Hypertension on the other hand was only 4.8% among the subjects found to be hypertensive. These rural populations studied had higher blood pressure levels and higher prevalence of hypertension than similar populations in other African countries in spite of a low body mass index. These findings emphasize the need for more studies in other areas of Sierra Leone, especially urban areas, and calls for improved screening facilities for the early detection and treatment of hypertension in Sierra Leoneans.

Xenobiotics and xenoestrogens in fish: modulation of cytochrome P450 and carcinogenesis

As is the case with mammals, an ever-increasing number of cytochromes P450 (CYPs) are being characterized from fish. The focus of work on fish CYPs has been primarily on environmental induction of CYP1A by pollutants such as the polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins and dibenzofurans. This response has been the basis for a sensitive biomonitoring tool of ecosystem health for a number of years. Studies have documented a correlation between CYP1A induction, pollutant levels and tumor incidence, especially in bottom-dwelling species. The rainbow trout has been utilized as a tumor model to document the role of CYP1A modulation in the inhibition or promotion of cancer. Fish are also very responsive to the class of chemicals known as xenoestrogens. Recent evidence is presented documenting the modulation of CYPs by xenoestrogens and their potential role as modulators of the tumor response. In this paper, we summarize the current knowledge concerning the occurrence of CYPs in fish and focus on the role of CYP1A induction in environmental monitoring of various genotoxic carcinogens and in the modulation of cancer in the trout model. Finally, the important class of aquatic pollutants known as xenoestrogens have now been shown to modulate CYP levels perhaps leading to alterations in tumor response or other adverse effects.

Effect of intervention for psychological distress on rehospitalization rates in cardiac rehabilitation patients

Psychosocial factors affect the development of coronary heart disease and morbidity and mortality of patients with known coronary heart disease. A prior study has shown that psychological distress in patients with known coronary heart disease increased medical and economic costs. This study examined the effects of commonly available psychological interventions offered to patients entering cardiac rehabilitation after hospitalization for angina, myocardial infarction, angioplasty, or coronary artery bypass grafting. A total of 380 patients were screened with the Symptom Checklist-90-Revised (SCL-90-R). Those with T-scores > or = 63 (> or = 91 percentile) on the General Severity Index (GSI) subscale were randomly assigned to usual care or special intervention. Special intervention included a psychiatric evaluation, plus one to seven sessions of behavioral therapy. The percentage of patients rehospitalized for cardiac symptoms within 12 months of psychological evaluation was 43% for special intervention and 40% for usual care (NS). A correction for crossover between the treatment groups resulted in a favorable trend toward intervention, with 35% of the psychologically treated patients rehospitalized vs. 48% of the untreated patients (NS). Although there was a nonsignificant reduction of the SCL-90-R's GSI T-score, the depression score was significantly reduced in the special intervention group.

Dual skin testing with Mycobacterium avium sensitin and purified protein derivative to discriminate pulmonary disease due to M. avium complex from pulmonary disease due to Mycobacterium tuberculosis

Skin testing with Mycobacterium avium sensitin (MAS) RS 10/2 and purified protein derivative (PPD) was conducted on patients with pulmonary disease due to M. avium complex (MAC) or Mycobacterium tuberculosis (MTB) and no known immunodeficiency. Reactions > or = 5 mm to either MAS or PPD were present in 37 (84%) of 44 MAC patients and 28 (97%) of 29 MTB patients. MAC patients had a mean MAS reaction of 13.8 (+/-8.3) mm and a mean PPD reaction of 3.5 (+/-8.6) mm (P < .001). MTB patients had a mean MAS reaction of 17.9 (+/-9.4) mm and a mean PPD reaction of 22.9 (+/-11.4) mm (P < .001). MAS-dominant skin tests (MAS reaction > or = 5 mm larger than PPD reaction) were present in 32 (73%) of 44 MAC patients and 1 (3%) of 29 MTB patients. MAS-dominant skin tests had a specificity of 97% for discriminating MAC disease from MTB disease.

Modulation of aflatoxin-B1 hepatocarcinogenesis in trout by dehydroepiandrosterone: initiation/post-initiation and latency effects

Previously, we demonstrated that dehydroepiandrosterone (DHEA) enhances aflatoxin B1 (AFB1) hepatocarcinogenesis in trout when administered following AFB1 exposure. This paper examines the effect of DHEA on tumor latency and the comparative potency for DHEA to modulate AFB1 carcinogenesis when administered prior to and concurrent with AFB1 compared with a post-initiation exposure. Trout were initiated by a 30 min water bath exposure to 10 p.p.b. AFB1. At 3 months post-initiation, animals were started on either control diet or a diet containing 444 p.p.m. dehydroepiandrosterone (DHEA). Fifty trout per treatment were sampled prior to the start of experimental diets, and then at monthly intervals for the next 7 months and examined for the presence of tumors. Tumors were not detected in initiated controls until 7 months after initiation. In initiated trout fed DHEA, the first tumor was detected 5 months after initiation (after just 2 months of dietary DHEA). At 6 months post-initiation, 20% of the AFB1-initiated trout fed DHEA had tumors, while no tumors were visible in either AFB1-initiated controls or noninitiated trout fed DHEA. A second experiment was designed to determine if the enhancing effect of DHEA on AFB1 carcinogenesis is dependent on the time of DHEA administration relative to the time of AFB1 exposure, and if DHEA could be chemopreventive if administered prior to and concurrent with AFB1. Trout were fed one of two levels of DHEA (888 or 1776 p.p.m.) either prior to and during a 4-week initiation period of dietary AFB1 administration, or for 8 weeks following initiation with AFB1. At 9 months after initiation the livers were examined for tumors. Neither exposure protocol provided protection towards AFB1 hepatocarcinogenesis. The strongest enhancement occurred when DHEA was fed during the post-initiation period. Levels of p53 and p34cdc2 were decreased by DHEA treatment, indicating that DHEA may act through alterations in cell-cycle control.

Stiff-man syndrome. Results of interviews and psychologic testing

Thirteen patients with stiff-man syndrome (SMS) were studied with the Minnesota Multiphasic Personality Inventory (MMPI), the Self-Administered Alcoholism Screening Test (SAAST), the State-Trait Anxiety Inventory (STAI) profiles, and by telephone interviews. The mean MMPI, SAAST, and STAI were within normal limits; however, several patients had abnormal profiles. The results of telephone interviews revealed that 8 patients (62%) had been given at least 1 psychiatric diagnosis and 4 (31%) abused alcohol or were dependent on it. Two patients had a psychiatric diagnosis that preceded the onset of symptoms of SMS. The authors hypothesize that SMS patients have a gamma-aminobutyric acid deficiency or GABAergic neuron dysfunction that leads to psychiatric symptoms, including depression and chemical abuse. Clinicians treating patients with SMS must be alert to the possible presence of comorbid psychiatric illnesses in this patient population.

Utilizing increased response effort to reduce chronic hand mouthing

The effects of increased response effort on levels of hand mouthing, leisure engagement, and adaptive elbow flexion were investigated with 2 individuals who had been diagnosed with profound disabilities. Arm restraints designed to alter the amount of physical effort necessary to engage in hand mouthing were used. Results indicated that the treatment strategy reduced levels of hand mouthing but produced only small to moderate reductions in levels of leisure engagement and adaptive elbow flexion. At follow-up, the effects of increased response effort on hand mouthing and leisure engagement were maintained for both participants; however, the restraints were associated with substantial reductions in adaptive elbow flexion for 1 participant.

Temporal distributions of problem behavior based on scatter plot analysis

The scatter plot is a commonly used assessment tool for identifying temporal patterns in the occurrence of behavior problems. However, the extent to which such patterns are frequently observed is unknown because little research has evaluated the general utility of the scatter plot. We conducted a large-scale analysis of within- and across-day occurrences of problem behavior by conducting continuous observations of 20 individuals living in four residential facilities. Data were recorded during 30-min intervals throughout participants' waking hours for 30 days by direct care staff and were converted into scatter plot formats. Five sets of data were excluded from further analysis due to poor interobserver agreement (below 80%). Visual analysis of the remaining 15 scatter plots indicated that none showed any reliable temporal pattern of responding. However, when the data were transformed into aggregate "control charts" based on statistical process control procedures, 12 of the 15 sets of data revealed one or more 30-min intervals during which problem behavior was more likely to occur. Results are discussed in terms of the practicality of applying statistical analyses to scatter plot data and of collecting data for the length of time needed to show statistical significance. It was concluded that detailed functional or descriptive analyses, which would reveal cause-effect or correlational relationships between behavior and specific environmental events, may be both more precise and more efficient forms of assessment.

Bioaccumulation and clearance of microcystins from salt water mussels, Mytilus edulis, and in vivo evidence for covalently bound microcystins in mussel tissues

Over a period of 3 days saltwater mussels, Mytilus edulis, were fed a cyanobacteria, Microcystis aeruginosa, that contained a high concentration of microcystins. The mussels were killed on a periodic basis over the course of 2 months. Mussels were also collected at two sites were high levels of microcystins in tissues had been noted. A strategy based on the chemically unique nature of the C20 beta-amino acid, (2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6- dienoic acid (Adda), portion of the microcystins was used in conjunction with a protein phosphatase (PPase) assay to analyse for both covalently bound microcystins and free microcystins in the mussel tissues. The mussel PPase assay results were compared with the Lemieux oxidation gas chromatography-mass spectrometry (GCMS) analysis. Less than 0.1% of the total microcystin burden in the mussel tissue was found to be extractable with MeOH. Thus, direct evidence was provided for the existence of covalently bound microcystins in mussel tissues in vivo. The mussels rapidly cleared the covalently bound microcystins when transferred to untreated seawater. Within 4 days the total microcystin burden dropped from a high of 336.9 (+/- 45.8) micrograms/g wet tissue to 11.3 (+/- 2.6) micrograms/g. After 4 days postexposure until completion of the experiment the total levels remained below the detection limits of the GCMS method. The levels of free microcystins, extracted with MeOH and detected by the PPase assay, fell from 204 ng/g wet tissue to a residual 14 ng/g over a 53 day postexposure period. Presumably the bound microcystin present in the mussel tissue exists as a covalent complex with the PP-1 and PP-2A enzymes. We conclude that in any shellfish monitoring program it is the total tissue microcystin burden that needs to be considered.

Flt3 ligand synergizes with granulocyte-macrophage colony-stimulating factor or granulocyte colony-stimulating factor to mobilize hematopoietic progenitor cells into the peripheral blood of mice

Peripheral blood progenitor cells (PBPC) are increasingly being used in the clinic as a replacement for bone marrow (BM) in the transplantation setting. We investigated the capacity of several different growth factors, including human flt3 ligand (FL), alone and in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF ) or granulocyte colony-stimulating factor (G-CSF ), to mobilize colony forming cells (CFU) into the peripheral blood (PB) of mice. Mice were injected subcutaneously (SC) with growth factors daily for up to 10 days. Comparing the single agents, we found that FL alone was superior to GM-CSF or G-CSF in mobilizing CFU into the PB. FL synergized with both GM-CSF or G-CSF to mobilize more CFU, and in a shorter period of time, than did any single agent. Administration of FL plus G-CSF for 6 days resulted in a 1,423-fold and 2,717-fold increase of colony-forming unit-granulocyte-macrophage (CFU-GM) and colony-forming unit granulocyte, erythroid, monocyte, megakaryocyte (CFU-GEMM) in PB, respectively, when compared with control mice. We also followed the kinetics of CFU numerical changes in the BM of mice treated with growth factors. While GM-CSF and G-CSF alone had little effect on BM CFU over time, FL alone increased CFU-GM and CFU-GEMM threefold and fivefold, respectively. Addition of GM-CSF or G-CSF to FL did not increase CFU in BM over levels seen with FL alone. However, after the initial increase in BM CFU after FL plus G-CSF treatment for 3 days, BM CFU returned to control levels after 5 days treatment, and CFU-GM were significantly reduced (65%) after 7 days treatment, when compared with control mice. Finally, we found that transplantation of FL or FL plus G-CSF-mobilized PB cells protected lethally irradiated mice and resulted in long-term multilineage hematopoietic reconstitution.

Inhibition of 2-amino-3-methylimidazo[4,5-f]quinoline-DNA adducts by indole-3-carbinol: dose-response studies in the rat colon

Indole-3-carbinol (I3C) inhibits the formation of colonic aberrant crypt foci and DNA adducts in rats given heterocyclic amine colon carcinogens, such as 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). Mechanism studies indicate that I3C induces cytochromes P4501A1 and 1A2 (CYP1A1 and CYP1A2), isozymes that respectively metabolize IQ via ring hydroxylation or activate the carcinogen by N-hydroxylation. The present study examined the dose-response for induction of CYP1A1 versus CYP1A2 by I3C, and compared the profiles of induction with the dose-response for inhibition of IQ-DNA adducts in the colon of the F344 rat. Dietary equivalent doses of I3C in the range 100-1000 p.p.m. increased in a dose-related manner both ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) activities in the liver and colonic mucosa, and Western blots showed a corresponding induction of CYP1A1 and CYP1A2 proteins. However, dietary equivalent doses of I3C in the range 10-25 p.p.m. (i) reduced hepatic EROD and MROD activities and CYP1A protein levels compared with controls, (ii) increased the ratio of CYP1A2 versus CYP1A1, and (iii) activated IQ to a more potent mutagen when liver microsomes from rats given I3C were used for metabolic activation in the Salmonella assay. Rats given a single oral dose of I3C shortly before administering IQ (5 mg/kg body wt, p.o.) exhibited dose-related inhibition of colonic IQ-DNA adducts in the range 25-100 p.p.m. I3C, reaching 95% inhibition at doses > or = 100 p.p.m. I3C, but IQ-DNA adducts were elevated slightly at the lowest I3C dose as compared with the controls. The possible significance of the low versus high dose effects of I3C are discussed in the context of human dietary exposures to I3C and the reported chemopreventive mechanisms of I3C in vivo.

Induction of T cell adhesion to extracellular matrix or endothelial cell ligands by soluble or matrix-bound interleukin-7

The putative effects of interleukin (IL)-7, operating in the context of extracellular matrix (ECM), on the adhesion of human T cells were examined. Recombinant human, IL-7 was found to bind ECM or fibronectin (FN) with IC50 values of 10-100 nM. Nanogram amounts of both soluble and, especially, FN- or ECM-bound IL-7, which differentially affected the morphologies of FN-adherent T cells, induced the adhesion of resting CD4+ and CD8+ T cells in dose-dependent and beta 1 integrin-dependent manners. Under static and flow conditions, soluble IL-7 also induced the binding of unstimulated T cells to vascular cell adhesion molecule-1, suggesting that this cytokine can also modulate integrin binding to endothelial cell ligands. The effects of affinity modulation by IL-7 of FN-specific beta 1 integrins depend on the presence of soluble FN, which inhibited T cell adhesion to FN induced by FN-bound IL-7 or by an integrin-specific affinity-modulating monoclonal antibody, but not by soluble IL-7 or phorbol 12-myristate 13-acetate. These findings provide an example of a major ECM integrin ligand, FN, which is capable of modulating its adhesive interactions with specific immune cells by associating with and presenting a cytokine in a bio-active state.

Psychiatric consultations in stiff-man syndrome

BACKGROUND

Stiff-man syndrome is a rare central nervous system disease first described nearly 40 years ago. Its cause has been attributed to both neurologic and psychiatric processes. In recent years, it has been accepted as a neurologic condition in which the gamma-aminobutyric acid (GABA) system malfunctions, probably because of an autoimmune process. Published reports that have described psychiatric manifestations of the disease have relied on descriptions of one or two cases and literature reviews.

METHOD

We reviewed the medical records of 24 patients with confirmed stiff-man syndrome, 12 of whom had received psychiatric consultation. This review was done to better determine the psychiatric manifestations of stiff-man syndrome.

RESULTS

Retrospective analysis of these 12 cases showed that the most common psychiatric symptoms were anxiety, depression, and alcohol abuse.

CONCLUSION

We speculate that the GABA system is involved in both the neurologic and psychiatric symptoms of these patients. Psychiatrists have a significant role in the management of patients with stiff-man syndrome and may be expected to manage anxiety, depression, and substance misuse.

Long term dietary indole-3-carbinol inhibits diethylnitrosamine-initiated hepatocarcinogenesis in the infant mouse model

Indole-3-carbinol (I3C), a natural component from cruciferous vegetables, has been demonstrated to be a modulator of carcinogenesis in various animal models. Along with the promising perspectives of I3C as a possible chemopreventive agent for human breast cancer, some concerns have been raised regarding the tumor-promotional potency of this compound in other target organs. In this study we examined the hepatic tumor-modulatory properties of I3C fed to C57BL/6J mice, initiated with diethylnitrosamine (DEN). Infant male mice were initiated with 0, 2 or 5 mg/kg DEN (i.p. injection) at 15 days of age. Mice were weaned 9 days later and immediately put on AIN76A semipurified diet (with no antioxidants) containing 0 or 0.15% (1500 ppm) I3C. In addition, at the age of 2 months, one group of mice initiated with 2 mg/kg DEN was injected i.p. with a single dose (20 mg/kg) of 3,4,5,3',4',5'-hexachlorobiphenyl (HCB), to serve as a positive control group for promotion. Mice were sampled for hepatic tumors at the age of 6 or 8 months. Each sampled group contained 11-12 mice except the HCB group (nine animals). After 8 months, there was a statistically significant (P < 0.0005) inhibition of hepatocarcinogenesis observed for I3C-fed animals initiated with the high dose of DEN. A single injection of HCB at 2 months of age significantly (P = 0.0003) enhanced hepatocarcinogenesis in mice initiated with 2 mg/kg DEN. There was no statistically significant difference between groups sampled at 6 months of age. Our observations indicate that long term administration of I3C in the diet inhibits DEN-initiated hepatocarcinogenesis in the infant mouse model.

Neutrophil maturation of CD34+ cells from peripheral blood and bone marrow in serum-free culture medium with PIXY321 and granulocyte-colony stimulating factor (G-CSF)

Bone marrow (BM) or peripheral blood (PB) CD34+ cells were cultured for 12 days in serum-free culture medium containing PIXY321 (IL-3/ GM-CSF fusion protein) with or without periodic supplements of granulocyte-colony stimulating factor (G-CSF). The cultures were evaluated at day 12 for total cell proliferation (fold increase from day 0), neutrophil differentiation by flow cytometry, using dual staining with CD15-FITC and CD11b-PE, and morphology using Wright-Giemsa and granule staining. In cultures containing PIXY321 where 6000 U/ml of G-CSF was added days 0 and 6, there was no significant difference (p > or = 0.05) in cell proliferation or the percent of CD15+/CD11b+ cells when compared with cultures with PIXY321 alone. ELISA analysis showed G-CSF levels had declined by 90% after 3 days of culture. Further studies were performed to assess the benefit of supplementing lower concentrations of G-CSF (600 U/ml) at more frequent intervals. A significant increase (p < or = 0.05) in cell proliferation and percent CD15+/CD11b+ was observed when G-CSF was added on days 0, 3, 6, and 9 (every 3 days) as compared with those cultures with PIXY321 alone. CD34+ cell proliferation without G-CSF was 19.6 +/- 4.8-fold, with G-CSF added on days 0 and 6 was 28.7 +/- 6.4-fold, and with G-CSF added on days 0, 3, 6, and 9 was 45.9 +/- 10.6-fold. Percent of CD15+/CD11b+ cells was 19.0 +/- 4.6%, 38.2 +/- 7.2%, and 58.5 +/- 6.5%, respectively, in these cultures. We observed more CD15+/CD11b+ cells, myelocytes/metamyelocytes, and secondary granule staining in cultures with G-CSF added on day, 0, 3, 6, and 9 as compared with cultures with G-CSF added on days 0 and 6 or no G-CSF added. We conclude that PIXY321 and G-CSF act synergistically on the in vitro proliferation and neutrophil differentiation of BM and PB CD34+ cells and that frequent supplements of G-CSF facilitate neutrophil differentiation.