Efficacy of ivermectin delivered from a sustained-release bolus against gastrointestinal nematodes in field grazing calves in Nyandarua district of Kenya

The effect of ivermectin delivered by an orally administered prototype sustained-release (IVM SR) bolus was evaluated over a period of 140 days using 12 steers aged approximately 8-10 months and ranging in weight from 150 to 175 kg. They were allocated to two groups of 6 steers each by restricted randomization based on their liveweight. Each of the treatment group received an IVM SR bolus designed to deliver 12 mg of the ivermectin/day for 135 days. The other group was designated as non-medicated controls. The groups were placed on adjacent 3 acre paddocks obtained by sub-dividing of 6.0 acre permanent pasture which had previously been grazed by young untreated cattle so exposing experimental steers to a similar challenge of a contaminated paddock. The faecal egg counts, herbage larval counts and worm burdens of the major gastro-intestinal nematodes of cattle were significantly reduced by the use of the IVM SR boluses. These parasitological effects were reflected in the increased liveweight gains in the IVM SR bolus-treated steers. The control steers required occasional salvage treatments over the trial period and the herbage on their paddock was heavily contaminated with infective larvae as reflected in the high worm burden in the control steers necropsied at trial termination and in tracer calves introduced into the paddocks during the initial (Day 31), interim (Day 69) and final (Day 100) stages of the experiment.

The effect of repeated moves to clean pasture on the build up of gastrointestinal nematode infections in calves

The build up of gastrointestinal nematode infections was followed in two grazing experiments. Both experiments included four groups of six calves, a permanently housed non-infected control group and three groups which were grazed from May to October. One of these was moved to aftermath in the beginning of July, the second in the beginning of July and August and the third in the beginning of July, August and September. The build up of gastrointestinal nematode infections was followed by performing faecal egg counts, differentiation of faecal larval cultures, pasture larval counts, serum pepsinogen values, serum antibodies against Cooperia oncophora, weight gain and worm counts. In the second experiment four of the principal trial animals of each group were treated with oxfendazole and subsequently challenged with 100,000 larvae of Ostertagia ostertagi to examine development of immunity against O. ostertagi. The faecal egg counts and the worm counts of the sentinels necropsied in July indicated low initial infections in both experiments. Infection levels in experiment 1 remained low in each group until the beginning of September. However, during the last month, moderate to high infections were acquired by the groups which were moved once or twice. In contrast, low to moderate infections were maintained in the group moved three times. In the second experiment moderate C. oncophora burdens were already observed in the sentinels grazed until the beginning of August. Tracers grazing in August-September with the group moved once acquired high O. ostertagi and C. oncophora infections, whereas those grazed with both other groups acquired moderate infections. In October high infections with both species occurred in the groups moved once and twice, whereas low to moderate infections were observed in the group moved three times. The challenge infection demonstrated a reduction of establishment of O. ostertagi of approximately 70% in all three groups on pasture. The results demonstrate that moving calves at monthly intervals to clean pasture can be an effective method for the control of parasitic gastroenteritis. In addition, the data indicate that it is essential that the last move does not occur more than 1 month before the end of the grazing season.

Pathogenicity and immunogenicity of different isolates of Teladorsagia circumcincta

The effects on liveweight gain and development of immunity were studied in lambs trickle infected for 8 weeks with either a benzimidazole-resistant isolate (Moredun ovine resistant isolate, MORI), a multiple benzimidazole + ivermectin-resistant isolate (Moredun caprine resistant isolate, MCRI) or an unselected susceptible isolate (Moredun ovine susceptible isolate, MOSI) of Teladorsagia circumcincta. Plasma pepsinogen concentrations of infected groups were significantly elevated compared to an uninfected control group (P < 0.001) by day 14. The liveweight gains varied markedly but there were no statistical differences between the infected and uninfected control groups at any point in time during the study. Lambs infected with the MORI had significantly lower faecal consistency scores than the other challenged groups on days 7 and 14 (P < 0.05) but from day 21 onwards, faecal consistencies were similar in all of the groups. There was a notable difference in the pre-patent periods of the different isolates with the MOSI producing positive faecal egg counts (FECs) by day 14 of the study. The FECs remained reasonably low once infections had reached patency and there were no further differences between the groups. Following administration of anthelmintic to remove residual worms from the trickle infection, no differences between the infected groups in terms of worm burden or mucosal mast cell numbers were evident as a consequence of a single challenge infection. The changes in genetic code associated with enhanced resistance against anthelmintics do not appear to have resulted in any fundamental alteration of the pathogenicity and immunogenicity of these three isolates of Teladorsagia.

Long-term symptom patterns, endoscopic findings, and gastric histology in Helicobacter pylori-infected and -uninfected patients

There is a paucity of data on the long-term behavior of dyspepsia, endoscopic findings, and gastroduodenal histology in patients with or without Helicobacter pylori colonization. We evaluated these parameters during a period of 7 to 19 years (average, 12.3 years) by baseline and follow-up studies. In 36 patients studied, the pattern of gastroduodenal dyspepsia and esophagogastroduodenoscopy findings remained essentially unchanged in 67% and 56% respectively. Dyspepsia patterns did not correlate significantly with either endoscopic or histologic findings, including the severity or location of gastritis in the fundus or antrum, or the presence or absence of H. pylori gastritis. Of 36 patients with adequate biopsies of the fundus and antrum, H. pylori colonization with gastritis was present in 73% but not in 27%. Progression to various degrees of atrophic gastritis was noted in 100% with, and in none without, H. pylori gastritis. In the fundus, atrophy progressed from 14% to 56%, but intestinal metaplasia did not change. In the antrum, atrophy increased from 22% to 64% and intestinal metaplasia increased from 17% to 36%. No patient demonstrated dysplasia, but severe atrophy was seen in the fundus (6%) and antrum (11%). Only two patients (5%) had severe loss of glandular elements and very low pepsinogen I, and thus can be considered to have developed advanced gastric atrophy.

Persistently increased gastrin and decreased pepsinogen concentrations in serum from some patients with Graves' disease of triiodothyronine-predominant type and common type

This study aimed to investigate the cause of persistently increased serum gastrin concentration seen in some Graves' disease patients even when euthyroid during antithyroid drug treatment. The subjects studied consisted of three groups: 33 patients with a common-type of Graves' disease, 14 with triiodothyronine (T3)-predominant Graves' disease (characterized from previous studies as having potent immunologic abnormalities including greater concentrations of thyroid-stimulating antibodies together with larger goiter size), and a group of 20 normal subjects. Fasting serum gastrin concentrations in common Graves' disease patients were significantly higher than those of normal subjects (58.4 +/- 38.9 pmol/L vs. 37.8 +/- 18.9 pmol/L [mean +/- SD], p < 0.05). The serum gastrin concentrations were even greater in T3-predominant Graves' disease patients than common Graves' disease patients (162.9 +/- 224.0 pmol/L vs. 58.4 +/- 38.9 pmol/L, p < .05). Serum pepsinogen I (PGI) concentrations were significantly lower in the T3-predominant patient group than the common Graves' group (24.0 +/- 12.9 ng/mL vs. 39.7 +/- 19.6 ng/mL, p < .05). Serum ratios of PG I to PG II were significantly lower in the T3-predominant Graves' disease patients than normal subjects (3.59 +/- 2.66 vs. 5.97 +/- 1.56, p < .01). The ratios also had a significant (p < .05) inverse correlation with serum gastrin concentrations in T3-predominant Graves' disease patients. The results suggest that autoimmune gastritis is associated with Graves' disease, particularly in patients with potent thyroid-autoimmunity.

Agreement of endoscopic findings and serum pepsinogen levels as an indicator of atrophic gastritis

Serum pepsinogen I and II levels have recently become popular as indicators of atrophic gastritis in epidemiological studies. Previous studies show a significant association between serum pepsinogen levels and endoscopically diagnosed atrophic gastritis. This study assesses the level of agreement between the degree of atrophic gastritis as assessed by endoscopic examination and by serum pepsinogen assays. Study subjects were 200 outpatients at Aichi Cancer Center Hospital, Nagoya, Japan, who were endoscoped between February and August 1995. Agreement of the degree of atrophic gastritis was assessed by endoscopic examination and by serum pepsinogen levels. Agreement in assessing the extent of atrophic gastritis between the two methods was 57%, and the presence of atrophic gastritis was 79%. Serum pepsinogen assays identify the majority of patients with atrophic gastritis, although they are less useful in assessing the degree of atrophy in detail.

Gastric cancer and premalignant lesions in atrophic gastritis: a controlled trial on the effect of supplementation with alpha-tocopherol and beta-carotene. The Helsinki Gastritis Study Group

BACKGROUND

Vitamin E and beta-carotene are considered to decrease the risk of gastric cancer both in humans and in laboratory animals. We studied the effect of dietary supplementation with alpha-tocopherol and beta-carotene on the end-of-trial prevalence of premalignant and malignant lesions of the stomach in older men with atrophic gastritis.

METHODS

The study was carried out within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC study) in Finland, in which 29,133 male smokers aged 50-69 years were randomly assigned to receive daily 50 mg alpha-tocopherol, 20 mg beta-carotene, both of these agents, or placebo, for 5-8 years. Serum pepsinogen was determined at base line and after 3 years' supplementation to find men with atrophic gastritis. A low serum pepsinogen I level, indicating atrophic gastritis of the corpus area of the stomach, was found in 2132 men. These men were invited to have upper gastrointestinal endoscopy (gastroscopy), which was performed on 1344 subjects after a median supplementation time of 5.1 years.

RESULTS

Neoplastic alterations were found in 63 of the men (4.7%): 42 with definite dysplasias of low grade (moderate dysplasia), 7 with definite dysplasias of high grade (severe dysplasia), 11 with carcinomas (of which 7 were 'early' cancers), and 3 with carcinoid tumors. Neither alpha-tocopherol (relative risk, 0.98; 95% confidence interval, 0.57-1.69) nor beta-carotene (relative risk, 1.13; 95% confidence interval, 0.65-1.95) supplementation had any association with end-of-trial prevalence of gastric neoplasias after adjustment for other possible risk factors. The effect was not modified by base-line serum level or dietary intake of vitamins, prevalence of Helicobacter pylori infection, or other covariates.

CONCLUSIONS

We thus conclude that supplementation with alpha-tocopherol or beta-carotene for 5 years has no major impact on the occurrence of neoplastic changes of the stomach in older male smokers with atrophic gastritis.

The efficacy of Michel's dose and move system on gastrointestinal nematode infections in diary calves

The efficacy of a move to aftermath in July combined with moxidectin or fenbendazole treatment for the control of parasitic gastroenteritis (PGE) in calves was evaluated in three field experiments in the Netherlands. In all five treated groups high gastrointestinal nematode infections and PGE were prevented by a dose and move in July. Cooperia infections increased to moderate levels in two groups treated with moxidectin and one group treated with fenbendazole. In both other groups and also for Ostertagia in these three groups, low to extremely low infections were acquired. In the first experiment high primary infections, resulting in high faecal egg counts and a moderate increase of blood pepsinogen values occurred before the dose and move. Nevertheless, these primary infections were not high enough to result in PGE. In both other experiments primary infection levels were low and faecal egg counts increased to 100-650 eggs/g faeces at the end of the grazing season. The blood pepsinogen values of non-treated control groups demonstrated that it took more than a month after their move to aftermath before substantial reinfection occurred on the new pasture. In the first and the last experiment only, high Ostertagia and Cooperia infections developed in the control group at the end of the grazing season, though it did not result in clinical PGE. The experiments demonstrate all theoretical risks of the dose and move system: (1) PGE early in the grazing season as a result of high overwintered pasture infectivity. (2) PGE just before the move as a result of an early midsummer increase in pasture infectivity. (3) PGE around housing as a result of insufficient suppression of pasture infectivity late in the grazing season. (4) Underexposure to nematode infections due to a high suppression of nematode infections. Nevertheless, it can be concluded that under normal conditions the dose and move system remains to be a valuable and easily applicable system for the control of PGE.

Field evaluation of a topical doramectin formulation for the chemoprophylaxis of parasitic bronchitis in calves

A study was conducted to evaluate the efficacy of two topical treatments with doramectin on the season-long control of lungworm and gastrointestinal infections in first grazing season (FGS) calves. At the start of the study, 20 FGS calves were randomly allocated into two treatment groups of 10 animals each. Calves in the D-group were treated with doramectin pour-on on days 0 and 56, at a dosage of 500 microg kg(-1) BW: calves in the C-group were designated as controls. A permanent pasture was divided in two blocks and these were randomly allocated to the treatment groups. Throughout the study, tracers (n = 32) were grazed on each paddock at 3-week intervals. Clinical signs of parasitic bronchitis (PB) were observed in the C-group in July and this necessitated two salvage treatments with levamisole. From day 28, post-turnout lungworm larvae were recovered from faeces of the C-calves until housing. No signs of PB were observed in the D-group during the entire grazing season. Shedding of lungworm larvae in the principals of the D-group did not occur until 112 days post-turnout. From the data obtained from the tracer calves. it appeared that larvae had overwintered on both pastures. On the C-pasture, the number of lungworms recovered from the tracer calves gradually increased to a peak in September, whereas on the D-pasture, the increase was observed only at the end of the pasture season. Both strongyle faecal egg counts and pepsinogen levels were relatively low in both groups throughout the present study. At the end of the grazing period (day 161). the principals were housed and treated with oxfendazole. During the housing period, all principal animals (D- and C-groups) and a third group of four helminth free animals (N-group) received a challenge infection with Dictyocaulus viviparus. It appeared that the different exposure to the parasite during the grazing season resulted in different establishment rates, i.e.. group C < group D < group N. The present results show that overwintering of lungworm larvae occurs in Belgium and that in such conditions, doramectin pour-on given at turnout and at 8 weeks controls PB in calves during the first grazing season.

Gastrointestinal nematode infections of first-grazing season calves in Western Europe: general patterns and the effect of chemoprophylaxis

Research on the prevention of gastrointestinal nematode infections of cattle has mainly concentrated on comparing a specific chemoprophylactic treatment system to an untreated control group on a particular farm. Here, the results from analysis of 85 studies involving over 2000 first grazing season (FGS) calves put onto pasture for at least 4 months from late spring/early summer over a 26-year period in 13 countries in Western Europe are presented. Both control and chemoprophylactic treated FGS calf groups were considered. All chemoprophylactic systems (slow- and pulse-release boli, strategic treatments) were given early in the grazing season. Two general infection levels emerged--'sub-clinical' (32 studies) and 'clinical' (53 studies). The 'sub-clinical' infections were characterised by no clinical symptoms of parasitic gastroenteritis (PGE) being observed in the control groups. Mean faecal egg counts in the 'clinical' control groups were significantly higher than those for 'sub-clinical' control groups for almost the entire season with overall peaks of 275 and 100 EPG respectively. Maximum pasture larval counts were also significantly higher in the 'clinical' control groups with 44% of 'clinical' pastures > 10,000 L3 kg(-1) dry herbage by the end of the FGS, compared to only 15% of 'sub-clinical' pastures. There was a significant positive relationship between log transformed worm burdens from tracers put onto pastures for 2 weeks and the corresponding pasture larval count. No evidence of density dependence in tracer worm burden was observed. Weight gains in the 'clinical' control groups (375 g/day) were significantly lower than those of the 'sub-clinical' control groups (530 g/day). No symptoms of PGE were observed in any of the chemoprophylactic treated groups, but in those studies with an outbreak of PGE in the control group, the treated groups had significantly higher faecal egg and pasture larval counts than treated groups in 'sub-clinical' studies. The overall weight gain in chemoprophylactic treated calves in 'clinical' studies (600 g/day) was significantly lower than the chemoprophylactic treated calves in 'sub-clinical' studies (690 g/day), and was not significantly different from the weight gain of control calves in 'sub-clinical' studies. These results indicate that on heavily infected pastures, chemoprophylaxis will prevent PGE, but calves will still suffer production losses.

The effect of different infection levels on acquired resistance to gastrointestinal nematodes in artificially infected cattle

The objective of this study was to evaluate the effect of different infection levels of Ostertagia ostertagi and Cooperia oncophora in a simulated 'first grazing season' on the resistance of calves to an artificial challenge infection. The infection levels were determined by the infection schedules and the chemoprophylaxis used. Thirty six 7-11-month old Holstein-Friesian bull calves were randomly divided into four groups. The animals of group B received an ivermectin sustained release bolus (ISRB) on day 0. The calves of group D were treated on days 0 and 56 with a subcutaneous injection of doramectin (0.2 mg kg(-1) BW). Group C was the untreated control group. The calves of group N were used as helminth-naive controls, while the animals of groups B, C and D were trickle infected for 24 weeks. The infection schedules were designed to simulate the expected infection pattern for each treatment group under set-stocked conditions in temperate climate areas. After the last infection, all animals were treated with oxfendazole. One week later, all animals received a challenge infection of 50,000 O. ostertagi L3 and 100,000 C. oncophora L3, spread over 10 consecutive days. During the primary infection period the faecal egg output and the serum pepsinogen and antibody levels reflected the different levels of host-parasite contact between the groups (group C > group D > group B > group N). After the challenge infection, faecal egg counts, total Ostertagia burden, size of the adult worms and abomasal globule leucocyte counts all indicated a positive relationship between the level of Ostertagia infection during the primary infection period and the level of acquired resistance. A reduction of host-parasite contact during the primary infection period, as a consequence of the infection schedule and the chemoprophylaxis used, resulted in a diminished level of resistance to the artificial challenge infection with O. ostertagi. Faecal cultures and small intestine worm counts indicated that all previously infected groups had acquired a high degree of resistance to the Cooperia challenge infection.

Helicobacter pylori cytotoxic genotype is associated with peptic ulcer and influences serology

OBJECTIVE

We studied 146 patients with peptic ulcer disease (n = 72), antral gastritis (n = 58), or duodenitis (n = 16) to ascertain whether the cytotoxic genotype of Helicobacter pylori (Hp) is associated with peptic ulcer disease and/or antral gastritis and whether it influences the circulating levels of total anti-Hp antibodies, anti-cagA antibodies, and pepsinogens.

METHODS

A gastric juice sample was obtained from each patient. After DNA extraction, polymerase chain reaction was used to amplify the genes urease A (ureA), cagA, and vacA of Hp.

RESULTS

A significant association was found between peptic ulcer disease and the cytotoxic genotypes, characterized by the presence of s1 and m1 alleles of vacA and by cagA. Patients with a cagA-positive genotype showed a significant increase in anti-cagA antibodies and also had significantly increased circulating levels of pepsinogen C.

CONCLUSIONS

Cytotoxic Hp strains are mainly involved in determining peptic ulcer disease, but not antral gastritis. The higher levels of circulating pepsinogen C found in patients infected with cytotoxic genotypes may reflect the higher degree of inflammation sustained by these strains.

Gastrobiliary dysmotility in patients with chronic pancreatitis as assessed by a single noninvasive test

We simultaneously assessed gastric emptying and gallbladder contraction after oral administration of a liquid meal by noninvasive ultrasonography in 17 patients with chronic pancreatitis (CP) and in 17 healthy controls. Gastrointestinal (GI) transit was also assessed by a noninvasive radioopaque marker method. Exocrine pancreatic function was evaluated by analyzing pure pancreatic juice and by analyzing the autonomic nervous system by cardiovascular reflex tests. Patients with CP showed impaired gallbladder contraction at 15 min and hastened gastric emptying. The cause of the former is unclear, whereas the latter was closely related with decreased pancreatic lipase output, but not with autonomic dysfunction. GI transit time did not differ between controls and patients with CP. In conclusion, we succeeded in clearly demonstrating impaired gallbladder contraction and hastened gastric emptying in patients with CP by a single noninvasive test, ultrasonography. We also revealed for the first time that hastened gastric emptying is associated with insufficient pancreatic lipase output.

Response to challenge infection with Haemonchus contortus and Trichostrongylus colubriformis in dairy goats. Consequences on milk production

The objective of the study was to examine the ability of dairy goats to develop a response to nematode parasites of the digestive tract after a previous contact with the worms. One hundred dairy goats were initially divided into 2 groups. One remained free of parasites (not previously infected: NPI). The second group was infected thrice at 50 days interval with a mixture of Haemonchus contortus and Trichostrongylus colubriformis (previously infected: PI). After this initial exposure to nematodes, the goats were drenched with fenbendazole to eliminate the worms and remained free of parasites for 2 months around kidding. One month after kidding, 24 lactating dairy goats from each initial group were challenged with a mixture of H. contortus and T. colubriformis and parasitological, pathophysiological and milk production parameters were measured fortnightly to assess the effects of challenge infection and the response of the goats. No difference in parasite egg excretion was found between group NPI and PI after challenge infection. Similarly, no difference in worm counts was detected in 5 culled goats from each group killed one month post challenge. In contrast, differences between both groups were detected when considering the pathophysiological parameters (packed cell volume, inorganic phosphate and pepsinogen concentrations) with consequences of infection being more severe in the previously infected animals. Moreover, the milk production was also depressed in the PI group when compared to the NPI one. These results indicate that the response developed by adult dairy goats after the challenge infection was unable to limit the worm populations but could have pathophysiological repercussions and consequences on production.

Epidemiology of Mecistocirrus digitatus and other gastrointestinal nematode infections in cattle in Mindanao, Philippines

Over a period of 14 months, faecal and serum samples were collected monthly from cattle of 1 to 30 months old on three ranches (20-25 animals ranch-1 sample-1) in Mindanao, Philippines. Individual faecal egg counts, serum pepsinogen levels and Mecistocirrus digitatus specific antibodies were determined, and infective larvae from pooled faecal samples were examined. Post mortem worm counts were carried out on tracer calves (n = 16) that had been kept for 30 days with the herds on two of the ranches. A number of gastrointestinal nematode species were present: M. digitatus, Haemonchus placei, H. similis, Trichostrongylus axei, Cooperia punctata, C. pectinata, Bunostomum phlebotomum and Oesophagostomum radiatum. Strongyle eggs first appeared in the faeces of calves of two months old, egg counts peaked when animals were 3-6 months old, after which they steadily and significantly declined. Faecal egg output of M. digitatus increased up to the age of 10 months, after which there was a steady but not significant decline until the age of 24 months. In faecal cultures the relative proportion of Cooperia larvae decreased from over 70% in 0-6 month old animals to 30% in 19-24 month old animals, and a corresponding 30% increase in the proportion of Mecistocirrus was observed. Both serum pepsinogen and M. digitatus specific antibodies levels increased during the first year of life, and then remained at the same level in older animals. Whereas the total faecal egg output did not significantly vary throughout the year, worm counts from tracer calves indicated a marked seasonality in transmission.

Pepsinogen polymorphism in the Indian population and its association with duodenal ulcer

To date, there have been few studies on pepsinogen polymorphism. The present study examines the polymorphism of pepsinogen by PAGE in 155 duodenal ulcer cases and 92 control subjects. The Indian population presents a higher frequency of the B phenotype (associated with absence of the pg 5 fraction) and the C haplotype compared to other populations. Heterozygotes, in particular AC phenotypic individuals, are found to be associated significantly with the disease compared to control subjects. All the genes of the multigene complex controlling pepsinogen polymorphism seem to be interacting, thereby leading to such an association. Thus, studies at the gene level may be helpful in explaining the genetic etiology and heterogeneity of duodenal ulcer disease.

Helicobacter pylori genotypes influence serum pepsinogen C levels

BACKGROUND

Infection from Helicobacter pylori significantly influences pepsinogen A (PGA) and C (PGC) levels in serum. Increased PGA and PGC serum levels are observed in H. pylori positive patients, while a significant decrease is observed after eradication. Little is known about the relative role of H. pylori cytotoxic strains in this phenomenon. The aim of our study was to assess the influence of cagA genotype on circulating levels of PGA and PGC.

MATERIALS AND METHODS

We studied 81 consecutive H. pylori positive patients, 64 H. pylori negative patients and 18 healthy controls. H. pylori was evaluated histologically in two antral and two body biopsies (Giemsa and/or Warthin Starry staining). Extracted DNA was then submitted for PCR amplification of both the urease A and cagA genes. A serum obtained from each patient before endoscopy was used for specific radioimmunoassay measurement of PGA and PGC.

RESULTS

The urease A gene was found in all H. pylori positive patients, the cagA gene was detected in 55 H. pylori positive patients and in none of the H. pylori negative patients. PGA and PGC levels were significantly higher in H. pylori positive than in H. pylori negative patients. A significant association was found between cagA and raised serum PGC levels in patients with antral gastritis but not in patients with peptic ulcer. Serum PGA levels were not affected by cagA.

CONCLUSIONS

Our results indicate that cagA positivity may influence the circulating PGC levels, probably because it causes a higher grade of mucosal inflammation.

Gastric cancer, gastritis and plasma vitamin C: results from an international correlation and cross-sectional study. The Eurogast Study Group

Low intake of foods rich in vitamin C is associated with an increased risk of gastric cancer, and geographic variation in average vitamin C intake, therefore, could explain some of the wide international variation in gastric cancer rates. This multicentre study investigated the relationships between plasma levels of vitamin C, as an indicator of vitamin C intake, and gastric cancer rates, markers of gastritis and other socio-demographic variables. Fasting plasma samples from about 1,400 individuals from 9 centres in 7 countries worldwide were assayed for total vitamin C using a fluorometric assay. There was no association between average plasma vitamin C levels and either gastric cancer mortality or incidence rates in the populations studied. Therefore, variation in fasting plasma vitamin C levels, as an indicator of consumption of vitamin C, does not appear to explain any of the wide geographic variation in gastric cancer rates. Furthermore, there was no association between plasma vitamin C levels and Helicobacter pylori infection, low serum levels of pepsinogen A (as a marker of severe chronic atrophic gastritis) or the presence of DNA adducts in blood leukocyte DNA. Multivariate models showed that fasting plasma vitamin C levels were associated positively with female sex, higher levels of education, never having smoked and increasing height and negatively with number of cigarettes smoked per day and increasing weight. This suggests not only that gender and tobacco smoking, in particular, are important predictors of plasma vitamin C levels but also that their effects are consistent throughout the developed world.

Helicobacter pylori: prevalence, transmission, and serum pepsinogen II concentrations in children of a poor periurban community in Bangladesh

The aim of this study was to determine the age-specific prevalence of Helicobacter pylori infection in infants and children aged 1-99 months from a poor periurban community in Bangladesh. We also examined the frequency of infection among infants and their 53 immediate family members and evaluated the relationship between infection and fasting serum group II pepsinogen (pepsinogen II) concentration in 76 children. Sixty-one percent of 1-3 month-old infants tested positive for H. pylori; this rate declined steadily to 33% in children aged 10-15 months and then increased to 84% in children aged 5-8 years. The H. pylori infection rate was 2.5 times higher in children with illiterate mothers. No difference in infection rate was detected among the family contacts of infected vs. noninfected infants. H. pylori-infected children had significantly higher serum pepsinogen II concentrations than did noninfected children (P < .001). We conclude that infection with H. pylori is highly prevalent and occurs at an early age. An environmental factor or factors, rather than or in addition to intrafamilial spread of this infection, are important in poor communities of Bangladesh. The higher levels of serum pepsinogen II in H. pylori-positive children might indicate the presence of gastritis in such asymptomatic children.

Antigastric autoantibodies in Helicobacter pylori infection: implications of histological and clinical parameters of gastritis

BACKGROUND

It has recently been shown that humoral antigastric autoreactivities occur in a substantial number of Helicobacter pylori infected patients.

AIMS

To analyse the relevance of such antigastric autoantibodies for histological and serological parameters of the infection as well as for the clinical course.

METHODS

Gastric biopsy samples and sera from 126 patients with upper abdominal complaints were investigated for evidence of H pylori infection using histology and serology. Autoantibodies against epitopes in human gastric mucosa were detected by immunohistochemical techniques. Histological and clinical findings of all patients were then correlated with the detection of antigastric autoantibodies.

RESULTS

H pylori infection was significantly associated with antigastric autoantibodies reactive with the luminal membrane of the foveolar epithelium and with canalicular structures within parietal cells. The presence of the latter autoantibodies was significantly correlated with the severity of body gastritis, gastric mucosa atrophy, elevated fasting gastrin concentrations, and a decreased ratio of serum pepsinogen I:II. Furthermore the presence of anticanalicular autoantibodies was associated with a greater than twofold reduced prevalence for duodenal ulcer.

CONCLUSION

The data indicate that antigastric autoantibodies play a role in the pathogenesis and outcome of H pylori gastritis, in particular in the development of gastric mucosal atrophy.

Effect of chemoprophylaxis with an ivermectin sustained-release bolus on acquired resistance to gastrointestinal parasites in cattle

The influence of chemoprophylaxis with an ivermectin sustained-release bolus in the first grazing season on the resistance of cattle to gastrointestinal nematodes during the following grazing season was investigated. In 1993 and 1994 dairy replacement calves were either given one bolus at the start of their first grazing season or left untreated. The two groups were grazed separately on a pasture that was divided into two similar sized paddocks. Faecal egg counts, serum pepsinogen and antibody levels were measured to evaluate host-parasite contact. Pasture infection levels were estimated by pasture larval counts and worm counts in tracer calves. After winter housing the animals were monitored during their second grazing season on a pasture that was also divided into two similar sized paddocks. Acquired resistance to gastrointestinal nematodes was evaluated by faecal egg counts and weight gains. Again, pasture infection levels were determined and pepsinogen and antibody levels were measured. During the first grazing seasons gastrointestinal nematode infections were controlled very effectively by the bolus, as shown by the greater weight gains, the negligible faecal egg counts and the low serum pepsinogen and antibody levels in the treated calves. In contrast, all parameters showed extensive parasite-host contact in the untreated animals. The efficient prophylaxis in the treated groups resulted in low levels of larval contamination on the paddocks grazed by the treated animals, compared to moderate infection levels at the end of both first grazing seasons on the paddocks grazed by the untreated animals. During the second grazing seasons (1994 and 1995) the faecal egg output was low in all groups. Although in the previously treated animals faecal egg counts were consistently higher, the differences were minimal, resulting in comparable levels of larval contamination on both paddocks. Serum pepsinogen and antibody levels were not significantly different between the groups and indicated a similar level of larval uptake on both paddocks. No negative effect of the previous chemoprophylaxis on the clinical condition and the weight gain of the second season grazing animals was observed.

Helicobacter pylori independent chronological change in gastric acid secretion in the Japanese

BACKGROUND

Gastric acid secretion in Japanese subjects decreases with aging. One of the possible causative mechanisms of this attenuated acid secretion is speculated to be a Helicobacter pylori induced chronic gastritis. The infection rate of this microorganism has decreased recently in Japan.

AIMS

To investigate whether gastric acid secretion has altered over the past 20 years, and if so, what the influence of H pylori infection might be in the Japanese population.

SUBJECTS AND METHODS

Gastric acid secretion, serum gastrin and pepsinogen I and II concentrations, and H pylori infection were determined in 110 Japanese subjects in both the 1970s and 1990s.

RESULTS

Basal acid output as well as maximal acid output have greatly increased over the past 20 years, not only in individuals with H pylori infection but also in those without infection. Furthermore, subjects with H pylori infection tended to show decreased gastric acid secretion in comparison with those without infection, particularly in geriatric subjects. There was a positive correlation between gastric acid secretion and serum pepsinogen I concentrations.

CONCLUSIONS

In Japan, both basal and stimulated gastric acid secretion have increased over the past 20 years; some unknown factors other than the decrease in H pylori infection may play an important role in this phenomenon.

Effect of Helicobacter pylori eradication on gastric histology, serum gastrin and pepsinogen I levels, and gastric emptying in patients with gastric ulcer

OBJECTIVE

The evolution of gastritis and the behavior of basal and meal-stimulated gastrin release, pepsinogen levels, and gastric emptying of solids were studied in a series of consecutive patients with Helicobacter pylori-positive, uncomplicated, non-NSAID-related type I gastric ulcer over a follow-up period of 3 months after eradication therapy was begun.

METHODS

Before starting treatment (consisting of omeprazole 40 mg a day for 1 month and amoxycillin 1 g three times daily for 14 days), and for 3 months after ulcer healing, 16 patients had a series of functional examinations, including basal and meal-stimulated serum gastrin concentration, serum pepsinogen I levels, evaluation of gastric emptying of solids by means of serial ultrasonographic measurement of the gastric antrum area, and histological assessment of antral and corpus gastritis.

RESULTS

Double therapy resulted in the successful eradication of H. pylori in eight of 16 evaluable patients. In the group of H. pylori-eradicated patients, the mean scores of gastritis activity and inflammation in the antrum and corpus had fallen, 3 months after eradication. No significant changes in mean gastritis scores were observed in the case and control group with regard to intestinal metaplasia and atrophy in the antrum and corpus. In H. pylori-eradicated patients, the integrated gastrin response to meal, but not fasting gastrin concentration, fell significantly during follow-up, and serum pepsinogen I levels significantly decreased, compared with baseline. In contrast, the fasting and maximal antral area and the gastric emptying of solids remained unchanged over time. In the control group (but not the H. pylori-eradicated group), no significant modifications of any of the above-mentioned parameters were observed during follow-up.

CONCLUSION

Our findings suggest that in non-NSAID-related type I gastric ulcers, the eradication of H. pylori significantly reduces gastritis activity and inflammatory scores, but not atrophy and intestinal metaplasia, and modifies gastrin and pepsinogen I release in a short follow-up period. In contrast, H.pylori eradication does not significantly affect gastric emptying of solids, at least within a period of 3 months from therapy.

Diagnostic tests for Helicobacter pylori infection

The two major catagories of diagnostic methods for Helicobacter pylori are invasive tests, or those that require endoscopy, and noninvasive, or nonendoscopic, tests. Diagnostic tests that use endoscopy include rapid urease tests, histology, and culture. Tests for which esophagogastroduodenoscopy is not necessary include various methods of antibody detection and carbon-labeled urea breath tests. Most tests are accurate, although none works perfectly and no gold standard for diagnosis exists. This article reviews the diagnostic methods available to establish H. pylori infection status and identifies some common mistakes made in testing. The costs associated with H. pylori diagnosis are evaluated and some cost-effective approaches to testing are suggested. Finally, the article offers some guidelines on choosing the appropriate diagnostic test in different clinical situations to determine the H. pylori infection status.

Evaluation of cutoff levels for screening of gastric cancer using serum pepsinogens and distributions of levels of serum pepsinogen I, II and of PG I/PG II ratios in a gastric cancer case-control study

This study was carried out to determine the cutoff levels of serum pepsinogen (PG) I, II and their ratio of PG I/PG II for gastric cancer to establish a better screening system. Optimal cutoff levels for gastric cancer screening using serum pepsinogens were determined using Youden's index. The sensitivity, specificity and Youden's index for gastric cancer cases were calculated according to sex, age and the stage of gastric cancer, and the maximum Youden's index in each category was adopted as the cutoff level for gastric cancer screening using serum pepsinogens. The maximal Youden's index in all gastric cancer cases was 0.37, corresponding to a cutoff level of PG I < 40 (micrograms g/l) and PG I/PG II < 3.5. The sensitivity and specificity for gastric cancer cases of these cutoff levels were 0.50 and 0.87, respectively. In future, better criteria for gastric cancer screening have to be examined with the estimation of Youden's index in addition to other epidemiological methods such as ROC (receiver operating characteristic) curves and/or cost benefit analyses.