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Biomedical subjects

F Hunter

Publications and source records attributed to F Hunter.

At least 19 recordsLinked to original sources
PubMed2001

Regulation of intestinal apolipoprotein A-I synthesis by dietary phosphatidylcholine in newborn swine.

Phospholipid (PL) from both dietary sources and biliary secretions may be important in the regulation of intestinal apolipoprotein (apo) synthesis. We previously demonstrated the up-regulation of apo A-I secretion by phosphatidylcholine (PC) in a newborn piglet intestinal epithelial cell line. We hypothesized that dietary PC increases small intestinal apo A-I synthesis in vivo in the newborn piglet. Two-day-old female swine were fed by gavage for 48 h. Diets consisted of a formula containing 51% of calories as triacylglycerol providing 180 kcal/kg/24 h. The experimental group (+PC, n = 7) received 1 g/L added soybean PC, and the control group (-PC, n = 7) received no added PC. At the end of the study period, jejunal apo A-I, B, and A-IV synthesis was measured, and apo A-I mRNA levels were quantitated. Jejunal mucosal PL content and serum lipids and apo B and A-I levels were measured. Jejunal apo A-I synthesis was almost twice as high in the +PC group as compared to the -PC group with no difference in apo A-I mRNA levels. Jejunal content of PL was higher in the +PC group than in the -PC group. There were no differences in jejunal apo B and A-IV synthesis or serum levels of lipids and apo-lipoproteins between the two groups. Dietary PC supplementation in newborn swine up-regulated jejunal apo A-I synthesis. Apo A-IV synthesis, which is sensitive to fatty acid flux, was not significantly increased, which suggests a specific effect of PC on apo A-I synthesis. Lumenal PC may be important in the regulation of intestinal apo A-I synthesis in the neonate.

Animals↗
PubMed1999

Agricultural pesticides threaten the ecological integrity of northern prairie wetlands.

The northern Great Plains of North America has millions of small wetlands, and these are often dispersed through cultivated fields. We investigated relationship between pesticide occurrence and precipitation in selected wetlands in a 30.4 x 10(4) km2 area of the Great Plains with relatively uniform farming practices and 1,777,600 wetlands (southern Saskatchewan, Canada). By early July after pesticides have been applied to crops, the mean number of pesticides detected in wetlands ranged from 1.8 in regions with little precipitation (< 21 mm rain during the previous 15 days) to 3.2 in regions under higher rainfall (> 90 mm). The proportion of wetlands in which at least one pesticide exceeded Canadian guidelines for the protection of aquatic life increased from 0% to 60% over this same precipitation range. The maximum number of pesticides detected in a single wetland was six. Concentration of lindane in wetlands increased with increasing precipitation. Using geographic information on rainfall, wetland densities, area seeded to crops, and region specific relationships between pesticides and precipitation, we estimated the number of wetlands in Saskatchewan with elevated levels of pesticides. In early July, during 3 of the 6 years, the number of wetlands subjected to pesticide levels that exceeded guidelines for the protection of aquatic life was significant, ranging from 152,000 to 424,000 wetlands or 9-24%, respectively, of the total. Lindane and triallate exceeded the guidelines most frequently.

Agriculture↗
PubMed1998

Effect of feeding diets of varying fatty acid composition on apolipoprotein expression in newborn swine.

The purpose of this study was to determine the effect of chronic (1 wk) feeding of dietary triacylglycerol (TG) of varying fatty acid composition on small intestinal and hepatic apolipoprotein expression, as well as serum lipid and apolipoprotein concentrations, in newborn swine. Two-day-old female swine were fed one of three diets by gavage with the following lipid composition: medium-chain TG (MCT; MCT oil), intermediate-chain saturated TG (ICST; coconut oil), and long-chain polyunsaturated TG (LCPUT; safflower oil) at 753 kJ . kg-1 . day-1 with 51% of energy from fat. After 1 wk, serum lipids and apolipoprotein concentrations were measured, and jejunal apolipoprotein B (apo B) and apo A-I mass and apo B, apo A-I, apo A-IV, and apo C-III synthesis were measured. Liver was processed for determination of apo B and apo A-I mass and apo B, apo A-I, apo C-III, and beta-actin mRNA abundance by slot blot hybridization. Compared with the MCT and LCPUT groups, the ICST group had higher total serum cholesterol, TG, high-density lipoprotein (HDL)-cholesterol, and apo A-I concentrations. There were no differences among the three groups for intestinal apolipoprotein mass or synthesis. In liver, apo A-I mass was highest in the ICST group. Liver apo A-I and apo C-III mRNA abundance was highest in the ICST group. Among all three groups, hepatic apo A-I mass correlated significantly with plasma HDL-cholesterol concentrations, and serum TG concentrations correlated with hepatic apo C-III mRNA abundance. In conclusion, we found that in the newborn piglet, chronic feeding of ICST increases serum total cholesterol, TG, HDL-cholesterol, and apo A-I concentrations and hepatic expression of apo A-I and apo C-III mRNA, compared with feeding of MCT or LCPUT. We speculate that increased hepatic apo A-I expression may contribute to the higher serum HDL and apo A-I concentrations in the ICST animals. Increased hepatic expression of apo C-III with ICST feeding may contribute to the higher serum TG concentrations by apo C-III-mediated inhibition of the catabolism of triacylglycerol-rich lipoproteins.

Animals↗
PubMed1996

Intestinal expression of apolipoprotein A-IV and C-III is coordinately regulated by dietary lipid in newborn swine.

The purpose of this study was to determine the effects of dietary fatty acids on intestinal apolipoprotein (apo) A-IV and C-III expression in the newborn piglet. Two-day-old female piglets received one of three isocaloric formulas containing medium-chain triglycerides (TG) (MCT), intermediate-chain saturated TG (ICST), or long-chain polyunsaturated TG (LCPUT) by continuous duodenal infusion for 24 hrs. Control groups received a low-TG elemental formula infusion (LTG group) and a high-TG long-chain unsaturated lipid emulsion infusion (HTG group). Jejunal synthesis of both apo A-IV and C-III was increased by all infusions compared to the LTG group. Apo A-IV and C-III mRNA levels paralleled synthesis levels except for apo C-III with the MCT diet, where regulation appeared to occur at the translational level. Among all groups, apo A-IV synthesis and mRNA abundance were linearly correlated with that of apo C-III.

Animals↗
PubMed1996

Effect of acute feeding of diets of varying fatty acid composition on intestinal apolipoprotein expression in the newborn swine.

The purpose of this study was to determine the effects of dietary fatty acids of varying chain lengths and degrees of saturation on intestinal apolipoprotein (apo) B and A-I expression in the newborn piglet. Two-day-old female piglets received one of three isocaloric formulas containing 48% of total calories (120 kcal/kg/24 h) as medium-chain triglycerides (MCT) from MCT oil, intermediate-chain saturated triglycerides (ICST) from coconut oil, or long-chain polyunsaturated triglycerides (LCPUT) from safflower oil by continuous duodenal infusion for 24 h. After in situ radiolabeling, jejunal and ileal mucosal apo B-48 and A-I were immunoprecipitated, and synthesis was expressed as percentage of total protein synthesis. Mucosal apo B and A-I mass was measured by ELISA as nanograms of apoprotein/microgram of total protein. Fifty percent less apo B jejunal synthesis was present in the ICST group versus the MCT and LCPUT groups (0.67 +/- 0.07, 1.19 +/- 0.20, and 1.25 +/- 0.15, respectively, mean +/- SEM, p < 0.05). Jejunal apo B mass was lower in the MCT group versus the ICST and LCPUT groups (0.10 +/- 0.02, 0.21 +/- 0.03, and 0.16 +/- 0.03, respectively, p < 0.05). Ileal apo B synthesis was lowest in the ICST group. No differences were found in ileal apo B mass. Two-fold higher jejunal apo A-I synthesis was found in the LCPUT group versus the MCT and ICST groups (14.18 +/- 1.69, 7.56 +/- 2.63, and 6.36 +/- 0.58, respectively, p < 0.01). No differences were found for jejunal apo A-I mass. In the ileum, the only difference was a higher apo A-I mass in the LCPUT group (p < 0.05). We conclude that in the newborn piglet intestinal apo B and A-I expression is acutely and differentially regulated by dietary lipid varying in fatty acid chain length and saturation. The patterns of regulation are complex and vary among specific apolipoproteins and regions of the small intestine and include co- and posttranslational mechanisms.

Animals↗
PubMed1995

Determinants of Helicobacter pylori infection and chronic gastritis.

The epidemiology of chronic gastritis was studied before recognition of Helicobacter pylori as its major cause. This case-control study was conducted in an attempt to elucidate causal associations for H. pylori infection and chronic gastritis. A questionnaire emphasizing diet and lifestyle was administered before gastroscopy to patients attending the gastroenterology clinic of Charity Hospital of New Orleans. H. pylori status and histopathology were evaluated independently to classify patients as cases or controls. A positive association was found between H. pylori infection and African American ethnicity as well as smoking. A strong interaction between race and smoking was found. Adequate intake of antioxidant micronutrients, especially vitamin C, was negatively associated with infection prevalence. H. pylori infection was strongly associated with an increased risk of atrophy (odds ratio (O.R.) = 6.4) and intestinal metaplasia of the gastric mucosa (O.R. = 4.7). Both gastric conditions increased in prevalence with age. Intake of antioxidant micronutrients was negatively associated with the risk of atrophy after adjustment for H. pylori infection.

Adult↗
PubMed1994

Helicobacter pylori and nucleolar organizer regions in the gastric antral mucosa.

The association of Helicobacter pylori with an increased risk of gastric adenocarcinoma has been documented, but its mechanisms have not been elucidated. This study explored these mechanisms by addressing the relationship between H pylori and the silver-staining nucleolar organizer regions (AgNORs) in the gastric antrum. The number of AgNORs per nucleus has been correlated with proliferative rate and ploidy. The results of gastric biopsies performed before and after treatment for H pylori showed that only patients who cleared the H pylori infection had a significant decrease in the number of AgNORs per nucleus. A positive association between AgNOR counts and the severity of polymorphonuclear infiltrate could be demonstrated in patients who did not clear H pylori infection. The authors concluded that H pylori infection alters the replication cycle of the antral mucosa, inducing hyperproliferation and possibly ploidy abnormalities. Whether these alterations are induced directly by the bacterium or by the acute inflammatory infiltrate remains undecided; the data in this study suggest a possible direct effect of the polymorphonuclear leukocytes.

Adult↗
PubMed1994

Verifying the future of electronic eligibility verification.

Many vendors and potential users of eligibility verification systems know the obstacles that deter the widespread acceptance and implementation of the technology. On the following pages, executives of firms representing the payor, provider and clearinghouse communities express their perceptions regarding the status and need for online eligibility verification and its cost advantages.

Eligibility Determination↗
PubMed1994

Periodontal probes and probing.

Probing of the sensitive, soft periodontal tissues differs markedly from probing of the dental hard tissues and caries. Periodontal probing requires special skills as well as an understanding of the tissues being examined, the probing procedure and the use of an appropriately designed instrument. Periodontal probing seeks to complement the initial visual assessment of the status of the periodontal tissue. It has multiple roles: to assess the haemorrhagic response to physical pressure; to determine the presence of aetiological factors such as calculus, defective dental restorations and root erosion, and to determine the pocket dimensions. It is also essential that the periodontal tissues should not be traumatised during probing. These defined aims of probing can only be achieved by use of an instrument that is capable of performing these functions, is designed to be 'tissue friendly', suitable as a measuring instrument, and standardised to ensure reproducibility, particularly with respect to the recommended pressure of 20 g exerted during probing. In addition, the ideal probe should be suitable for use both in the clinical setting where precise data documentation is required on an individual patient basis, and for screening purposes, as in epidemiology. A probe designed to achieve these attributes

Dental Calculus↗
PubMed1993

Helicobacter pylori causes hyperproliferation of the gastric epithelium: pre- and post-eradication indices of proliferating cell nuclear antigen.

OBJECTIVE: To assess the effect of Helicobacter pylori (HP) eradication on the proliferation of the gastric epithelium by the expression of the proliferating cell nuclear antigen (PCNA). METHODS: Alcohol-fixed gastric biopsies taken before and after treatment for HP were immunostained with the PC-10 anti-PCNA monoclonal antibody and the labeling index was determined with an image analysis system. RESULTS: The mean PCNA-labeling index (LI) of 16 patients who remained HP positive did not change significantly (18.95 +/- 1.71 on first visit vs. 17.96 +/- 1.91 on second visit, mean +/- SEM). The mean PCNA LI of 31 patients who cleared HP was reduced significantly (19.95 +/- 1.77 on first visit vs. 14.13 +/- 1.29 on second visit, p < 0.001). Patients who were positive for HP at both first and second visit showed a significantly higher PCNA LI than normal control biopsies (13.05 +/- 1.70) (p < 0.05). CONCLUSIONS: These results indicate that the gastric mucosa infected with HP is in a state of hyperproliferation. Patients who cleared HP showed a significant histopathological improvement, reflected in the reduction in number of polymorphonuclear and mononuclear cell infiltrates, and a reduction in the amount of superficial mucosa damage. Prolonged hyperproliferation of the gastric epithelium exerted by HP infection could be a major factor for human gastric carcinogenesis.

Autoantigens↗
PubMed1992

High prevalence and persistence of cytotoxin-positive Helicobacter pylori strains in a population with high prevalence of atrophic gastritis.

Helicobacter pylori is strongly associated with both chronic gastritis and duodenal ulcer. Certain strains of H. pylori produce a vacuolating cytotoxin in vitro. At New Orleans Charity Hospital, concentrated culture supernatants from 119 of 144 (83%) H. pylori strains isolated from 86 patients at high risk of developing gastric cancer, caused vacuolization in HeLa S3 cells. Cytotoxin activity was neutralized by acid (pH 4) and basic (pH 10) solutions and proteases, and was precipitable by (NH4)2SO4, which suggests that the cytotoxin is a protein. In 66 of 86 (76.7%) patients, the H. pylori strains isolated from single or multiple sequential gastric biopsies had a vacuolating cytotoxin. These cytotoxin-positive H. pylori strains were isolated from 69% of patients with diffuse antral gastritis and 89% of patients with chronic atrophic gastritis. The latter lesion is considered a precursor of gastric cancer. The cytotoxicity persisted in sequential biopsies over an interval of several months, indicating persistence of these strains in the gastric mucosa. Fifty-eight percent (7/12) of the sera from cytotoxin-positive H. pylori-infected patients neutralized cytotoxin activity, whereas 20% (1/5) of sera from patients with H. pylori cytotoxin-negative strains and none of five H. pylori-negative patients' sera neutralized cytotoxin activity. The relevance of this cytotoxin in the pathogenesis of H. pylori-induced gastritis requires further study.

Adult↗
PubMed1991

Clinical trials as etiologic research tools in Helicobacter-associated gastritis.

The role of clinical trials as tools to elucidate the etiology of chronic gastritis is discussed. Three areas are briefly explored. The first one concerns the classification of chronic gastritis, a constellation of interconnected nosologic entities. The second refers to the histopathologic factors of chronic gastritis; preliminary results show that clearance of Helicobacter pylori decreases the inflammatory infiltrate and suggest that H. pylori alters cell ploidy. The third area refers to the multifactorial etiology of chronic gastritis and the role that clinical trials could play in its elucidation.

Gastritis, Atrophic↗
PubMed1989

Analysis of the spectrin binding domains of globin.

This study describes the results of binding studies between human spectrin and peptides obtained by trypsin digestion of human globin. The globin digest when passed through an affinity column of spectrin-coupled sepharose retained one peptide from both alpha and beta chains of globin. The absorbed peptides were eluted with 4 M guanidine hydrochloride and separated on a reverse phase column by high pressure liquid chromatography. Their amino acid sequence was determined and their position located in the globin molecule.

Amino Acid Sequence↗
PubMed1989

Campylobacter pylori-associated gastritis and immune response in a population at increased risk of gastric carcinoma.

A series of 169 consecutive patients from low socioeconomic strata attending the gastroenterology clinic of Charity Hospital in New Orleans were evaluated clinically and endoscopically. This general New Orleans population is known to be at increased risk of developing gastric carcinoma. The type of gastritis was identified histologically, and the presence of Campylobacter pylori was determined by culture and/or histology. The overall prevalence of C. pylori infection in this patient population was 71% (126/169). These findings were correlated with serum IgG antibody to C. pylori using an ELISA. Fifteen patients with neither demonstrable gastritis nor C. pylori served as negative controls and had low levels of IgG antibody to C. pylori. A strong correlation was found between Campylobacter detection by morphologic and/or culture technique and the presence of serum IgG antibody. For all patients examined, the sensitivity of the ELISA was 94.2% and the specificity 75.5%. The highest ELISA values for IgG antibody (sensitivity = 89%, specificity = 75%) were detected in patients positive for C. pylori, who also had diffuse antral gastritis with prominent lymphoid follicles. For patients with chronic atrophic gastritis and intestinal metaplasia, the sensitivity of the ELISA was 96% and the specificity 67%. The latter number may indicate underrepresentation of foveolar epithelium in biopsies with extreme intestinal metaplasia. Results suggest a high prevalence of chronic infection of C. pylori in this clinic population. The possible role of C. pylori in the development of precursor lesions of gastric cancer is discussed.

Adult↗
PubMed1986

Purification of spectrin and its subunits by high-performance liquid chromatography.

Technological and methodological advances in the techniques of structural and biological studies of proteins have reduced the required amount of sample. In conjunction with these advances, high-performance liquid chromatography (HPLC) has emerged as a technique of high utility for the purification of complex molecules. Using a combination of size-exclusion and reversed-phase HPLC and ionic buffers containing sodium dodecyl sulfate, the red cell membrane-associated high-molecular-weight polypeptide spectrin and its subunits have been purified. The system described in this paper is fast, reproducible and quantitative.

Chromatography, High Pressure Liquid↗
PubMed1986

Ultrastructure of the gastric mucosa harboring Campylobacter-like organisms.

The association between Campylobacter-like organisms (CLOs) and lesions of the gastric mucosa was studied in 59 consecutive biopsies. Hematoxylin and eosin and Warthin-Starry silver stains, as well as high-resolution light microscopy (HRLM) and transmission electron microscopy (TEM), were used. The organisms were found in intimate contact with foveolar cells showing abundant phagolysosomes and alterations of the intercellular complexes. CLOs also were seen in close proximity of parietal cells in resting phase, some of which showed degenerative changes. The findings are discussed in light of recent reports linking CLOs to the cause of gastritis.

Campylobacter↗
PubMed1986

Diet and chronic atrophic gastritis: a case-control study.

A hospital-based case-control study of gastric cancer precursor lesions was conducted in a high-risk black population in southern Louisiana. Ninety-three subjects with biopsy-proved advanced chronic atrophic gastritis were compared to two control series: a gastroscopy clinic series and a general hospital-admission series. Dietary case-control differences indicated a protective effect associated with fruit and vegetable intake and with dietary vitamin C and a risk elevation associated with milk consumption. The protective effect associated with consumption of fruits, vegetables, and vitamin C is consistent with findings for gastric cancer and with the etiologic hypothesis of intragastric nitrosation. A twofold increased risk was associated with cigarette smoking. Gastric juice pH, NO3-, and NO2- were determined for subjects undergoing gastroscopy, and comparisons were made between this high-risk U.S. group and a Colombian population with a much greater magnitude of risk; the latter had higher NO3- and NO2- levels. An increase in pH was associated with increasing severity of gastric lesions. Levels of pH and NO2- concentration were significantly correlated (P less than .0005); however, in Louisiana the large difference in NO2- concentration associated with pH elevation is not associated with histopathologic severity. Divergent trends with severity of lesions for NO3- concentration were seen in the two populations.

Adult↗