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Biomedical subjects

D Vaira

Publications and source records attributed to D Vaira.

At least 109 records · Page 6Linked to original sources
PubMed1995

Helicobacter pylori in patients with gastric and nongastric cancer.

OBJECTIVES: To compare the seroprevalence of Helicobacter pylori in gastric and nongastric carcinoma patients and to investigate the relationship between H. pylori, gastric cancer site, and histological type. METHODS: In a 24-month period, 307 gastric cancer patients (male/female: 185/122; age range 19-94 yr, mean 69 yr) were investigated by serology (IgG to H. pylori), histology, and urease test for H. pylori. One hundred and seventy-seven gastric cancers were in the antrum, 98 were in the corpus, and 32 were in the fundus; 227 were intestinal and 80 were diffuse type. In the same study period, we assessed the H. pylori seroprevalence in 162 patients with nongastric carcinoma (lung n = 41, breast n = 42, genitourinary n = 41, GI tract n = 22, others n = 16) (male/female: 84/78; age range 31-81 yr, mean 56 yr). RESULTS: The overall seroprevalence of H. pylori in gastric cancer and in nongastric cancer was 82 and 56%, respectively (p < 0.001). In asymptomatic blood donors (age range 55-65 yr) and in dyspeptic patients older than 60 yr, a seroprevalence of 55 and 58% was found, respectively, which is significantly lower (p > 0.001) than the gastric cancer patients but similar to the nongastric cancer population. No difference was found in the H. pylori status according to the gastric cancer site (83, 82, and 81% in the antrum, corpus, and fundus, respectively). Two hundred and twenty-seven gastric cancers [185 (81%) H. pylori-positive] were found to be of an intestinal type and 80 [66 (82%) H. pylori-positive] of a diffuse type (not significant). No age-related difference (below and above 60 yr) in H. pylori prevalence was observed within each cancer population, and, in both age groups, the seroprevalence of infection was higher in gastric cancer patients (86 and 81%) than in nongastric cancer patients (56 and 56%) (below and above 60 yr, respectively). CONCLUSION: H. pylori seroprevalence is significantly higher in gastric cancer compared with nongastric cancer patients. No differences were observed in H. pylori seroprevalence according to gastric cancer site or histological type. The higher H. pylori seroprevalence in gastric cancer patients is not age related.

Age Factors↗
PubMed1994

Prevalence of peptic ulcer in Helicobacter pylori positive blood donors.

This study aimed to determine the importance of raised antibodies to Helicobacter pylori in an asymptomatic population. A total of 128 asymptomatic blood donors who were seropositive for H pylori and consented to endoscopy were investigated. These subjects were from a population of 1010 blood donors screened for antibodies to H pylori. A questionnaire was completed to determine if any subjects had complained of symptoms, and they subsequently had endoscopy. Altogether 121 of 128 were positive for H pylori by histology and urease test and/or culture and all 121 had chronic active gastritis on histology. Twenty five of these subjects had peptic ulcer (20 duodenal, five gastric), a further 21 had erosive duodenitis, and two were found to have gastric cancer. H pylori associated peptic ulcer disease and duodenitis occur more frequently than previously recognised and this suggests that H pylori infection, even if asymptomatic, is of far greater clinical relevance than originally thought.

Adolescent↗
PubMed1994

Duodenal ulcer, Helicobacter pylori, and gastric secretion.

Patients with chronic dyspepsia were categorised by macroscopic appearance at oesophagogastroduodenoscopy as having duodenal ulceration (DU), other diagnosed lesions such as reflux oesophagitis, carcinoma of stomach, etc, or no organic lesion (non-ulcer dyspepsia, NUD). Material was collected to identify gastric infection with Helicobacter pylori (H pylori) by CP urease test, culture, and histological examination and to make the microscopic diagnosis of active chronic gastritis. Each patient in the DU and NUD categories was then invited to volunteer for a gastric secretion study in which maximal gastric secretion in response to histamine was measured. Sixty two gastric secretion tests were performed (31 DU, 31 NUD). The presence of H pylori was associated with active chronic gastritis (100%). DU patients secreted more acid than the NUD patients. H pylori positivity was associated with decreased maximal gastric secretion in both groups. There was a positive correlation between smoking and maximal acid output shown only in H pylori negative but not in H pylori positive patients. These findings were clear cut when all corrections of maximal gastric secretion were made for pyloric loss, duodenogastric reflux, and stature. This study failed to show any aetiological link between H pylori and DU by increased maximal gastric secretion.

Adolescent↗
PubMed1994

Enhanced mucosal interleukin-6 and -8 in Helicobacter pylori-positive dyspeptic patients.

OBJECTIVES: To determine the concentrations of interleukin-1 beta, interleukin-6, and interleukin-8 in tissue homogenates of mucosal biopsy specimens from Helicobacter pylori-positive and -negative patients. METHODS: In 43 consecutive patients who underwent upper gastrointestinal endoscopy, seven antral biopsies were taken; three specimens were used for cytokine determination and the remaining four biopsies were processed for H. pylori detection. Peripheral venous blood was collected and IgG to H. pylori was assayed by an ELISA technique. RESULTS: Twenty-nine of 43 patients (67%) were histologically positive for H. pylori; all had chronic gastritis. The mucosal levels of interleukin-6 and interleukin-8 were significantly higher in H. pylori-positive patients than in the negative patients (p < 0.001). A significantly higher percentage of interleukin-8 was found in patients colonized by H. pylori with active superficial chronic gastritis (85.7%), compared to quiescent superficial gastritis (12.5%) (p < 0.01), and the median and range were, respectively, 400 (0-1000) and 0 (0-200) pg/mg protein (p < 0.001). In patients with active superficial gastritis, a significant correlation between interleukin-6 and -8 was found (p 0.01). No difference was found regarding the mucosal levels of interleukin-1 beta according to the presence of H. pylori. CONCLUSIONS: These results suggest a possible pathogenetic role for interleukin-6 and interleukin-8 in H. pylori-associated gastritis.

Adult↗
PubMed1993

HIV-1 promoter activation following an oxidative stress mediated by singlet oxygen.

Various biological processes, such as photosensitization or inflammatory reactions, can generate singlet oxygen (1O2) as one of the major oxidative species. Because this oxidant can be generated either extracellularly or intracellularly, it can cause severe damage to various biological macromolecules, even to those deeply embedded inside the cells such as DNA. Sublethal biological modifications induced by different DNA-damaging agents can promote various cellular responses initiated by the activation of various cellular genes and certain heterologous viruses. Since 1O2 fulfils essential prerequisites for a genotoxic substance, we have examined the effects of an oxidative stress, mediated by this species, on cells harbouring a heterologous promoter-leader sequence derived from the human immunodeficiency virus type 1 (HIV-1). Our results demonstrate that HIV-1 long terminal repeat (LTR), integrated into the cellular DNA of epithelial cells, can be transactivated following an oxidative stress mediated by 1O2. In addition, using HIV-1 latently infected promonocytes or lymphocytes, it can be shown that virus reactivation can be induced through a sublethal dose of 1O2 generated intracellularly. An extracellular generation of 1O2 can promote a substantial lethal effect without HIV-1 reactivation. These data may be relevant to the understanding of the events converting a latent infection into a productive one and to the appearance of the acquired immune deficiency syndrome.

Cell Survival↗
PubMed1993

Gastric retention of sucralfate gel and suspension in upper gastrointestinal diseases.

This study was designed to compare by scintigraphy the gastric retention of a new dosage form of sucralfate as gel (Gastrogel) with that of sucralfate suspension in 25 patients with upper gastrointestinal symptoms referred for routine endoscopy. After endoscopy 4 subgroups were defined: macroscopically normal mucosa (n = 7), antral gastritis and/or erosions (n = 6), gastric ulcer (n = 6) and duodenal ulcer (n = 6). Each patient received either sucralfate gel or sucralfate suspension in equivalent doses (5 ml containing 1 g sucralfate). Both formulations were labelled with 111 MBq 99mTc-DTPA before administration. The mean value of t1/2 in the total group was significantly longer when patients were taking sucralfate gel (61.6 min) compared to sucralfate suspension (33.8 min) (P < 0.001). The mean values of t1/2 were significantly longer for sucralfate gel compared to sucralfate suspension also among the subgroups (macroscopically normal P < 0.02, antral gastritis P < 0.05, gastric ulcer P < 0.02 and duodenal ulcer P < 0.05). After 2 and 3 hours, the percentage residual activity in the gastric area was significantly higher following administration of sucralfate gel compared to sucralfate suspension. This study has shown that, compared to sucralfate suspension, sucralfate gel persists longer in the stomach of patients with gastritis and peptic ulcer.

Adolescent↗
PubMed1993

Serum pepsinogen I and II concentrations and IgG antibody to Helicobacter pylori in dyspeptic patients.

AIMS: To investigate the association between histologically confirmed gastritis, carriage of Helicobacter pylori and pepsinogen (PG) I and PG II concentrations. METHODS: Prospective study of 81 dyspeptic patients undergoing upper gastrointestinal endoscopy was made. The extent of gastric mucosal inflammation and the presence of H pylori was determined, and serology to evaluate PG I and II concentrations and IgG titres to H pylori was carried out. RESULTS: The presence of H pylori was strongly correlated with high IgG antibody titres to H pylori and gastritis. Patients who were H pylori positive had significantly higher PG I and PG II concentrations and a significantly lower PG I:PG II ratio than patients who were negative for H pylori. In 13 patients with duodenal ulcer and H pylori positive gastritis serum PG I concentrations were significantly higher than in H pylori positive patients without duodenal ulcer. Significant correlations were found between the age of patients and serum PG II, the PG I:PG II ratio, IgG antibodies to H pylori, the severity of body gastritis and H pylori infection, and between the degree of gastritis in the body of the stomach and the PG II concentration. CONCLUSIONS: Serum PG I and II concentrations, together with a fall in the PG I:PG II ratio, could be used as predictors of H pylori infection as well as serum IgG antibody response to H pylori.

Adolescent↗
PubMed1992

Eicosanoid synthesis and Helicobacter pylori associated gastritis: increase in leukotriene C4 generation associated with H. pylori colonization.

The importance of pro-inflammatory leukotriene C4 in Helicobacter pylori (H. pylori) associated gastritis in man is unknown. Fresh gastric biopsy specimens from 28 dyspeptic patients were obtained: 10 showed normal antral histology with no evidence of H. pylori, the remaining 18 patients exhibited histological gastritis and were H. pylori positive as assessed by histology, culture and urease test. Twelve of these 18 patients received 240 mg twice daily colloidal bismuth subcitrate for four weeks before re-endoscopy. Gastric biopsies from H. pylori positive patients were incubated under basal and Ca(2+)-ionophore mediated conditions: Radioimmunoassay analysis of the supernatant showed basal release of prostaglandin E2 and leukotriene C4 was slightly but not significantly elevated in H. pylori positive mucosa. However in H. pylori positive mucosa there was an 85% increase in leukotriene C4 synthesis when biopsies were incubated with ionophore, compared to only 13% increase in H. pylori negative mucosa (p less than 0.02). After eradication of H. pylori by colloidal bismuth subcitrate, there was a clearance of inflammatory cell infiltrate as assessed by histology and a significant reduction in ionophore-mediated leukotriene C4 formation compared with before treatment (p less than 0.02). These results suggest that H. pylori gastritis is associated with increased capacity to generate leukotriene C4, which may amplify the damaging effects of the bacteria on gastric mucosa.

Adult↗
PubMed1992

Eighteen month follow up of Helicobacter pylori positive children treated with amoxycillin and tinidazole.

Sixty three children with dyspepsia (mean age 12 years, range one to 18, M/F 41/22) were Helicobacter pylori positive by histology of gastric antral biopsy specimens and were treated with a six week course of amoxycillin (50 mg/kg) and tinidazole (20 mg/kg). The endoscopic diagnoses were: normal (16), nodular gastritis (19), oesophagitis (four), duodenal ulcer (13), and gastric ulcer (11). H pylori was eradicated in 54 (87%) and histological gastritis resolved in 51 and was improved in the other three. Repeat investigation was offered at six monthly intervals. Reinfection was found in three of 34 (9%) at six months, in none of 22 at 12 months, and in two of 18 (11%) at 18 months, yielding an 18 month cumulative relapse rate of 20%. Children with persisting infection despite treatment remained positive during follow up. Serum H pylori IgG concentrations fell after treatment (p < 0.001), and for individual children during follow up there was a progressive decline, but an increased concentration indicated recurrence. After eradication of H pylori by combined amoxycillin and tinidazole treatment, only a minority of children relapse during the ensuing 18 months.

Adolescent↗
PubMed1992

Endoscopic therapy for bile duct stones in a geriatric population.

During the 5 year period to May 1988, 137 consecutive patients (age range, 65-102 years; median 84 years) with a diagnosis of choledocholithiasis, were referred to The Middlesex Hospital Geriatric Department. Endoscopic sphincterotomy was successful in 96.2% of cases and immediate biliary drainage was achieved in all but one of these patients. Stones were cleared endoscopically in 73.3% and surgically in 4.7% of cases. Long-term stenting was employed in 14.3% of patients. The 30 day mortality after endoscopic or surgical treatment was 4.7% (six deaths), although death was probably unrelated to therapy in half the cases. Deaths were due to procedural cardiorespiratory arrest (1), pancreatitis (1), pneumonia (2) and cerebrovascular accident (2). Endoscopic treatment is effective even in a high-risk geriatric population. After sphincterotomy patients with intact gall bladders should be managed expectantly.

Aged↗
PubMed1992

Double blind trial of colloidal bismuth subcitrate versus placebo in Helicobacter pylori positive patients with non-ulcer dyspepsia.

We have carried out a double blind placebo controlled trial to assess the effects of treatment with colloidal bismuth subcitrate in Helicobacter pylori associated non-ulcer dyspepsia. Eighty patients with dyspepsia, normal upper gastrointestinal appearances at endoscopy and H pylori associated active chronic gastritis on histology of gastric antral biopsies were included in the trial. The patients were randomised to receive colloidal bismuth subcitrate 240mg twice daily for four weeks or matching placebo and were reassessed four weeks after completing treatment. Twenty-six patients (67%) receiving colloidal bismuth subcitrate had normal histology or improved inflammation compared with five (13%) receiving placebo (p less than 0.001), and symptoms were absent or improved in 32 (82%) and two (5%) respectively (p less than 0.001). Serum IgG level was a marker of infection, and fell with successful treatment. Colloidal bismuth subcitrate is effective treatment for H pylori associated non-ulcer dyspepsia with improved gastric antral histological appearances and has a beneficial effect on symptoms.

Adult↗
PubMed1992

Detection of Helicobacter pylori-like organisms in the stomach of some food-source animals using a monoclonal antibody.

To investigate a possible animal reservoir of Helicobacter pylori, 15 pigs, 15 rabbits and 5 cows slaughtered for consumption were studied. Raised serum IgG levels were found in 93% of the pigs and 87% of the rabbits, but levels were normal in the cattle. In the controlled testings three of 22 humans had elevated IgG to H pylori and in all three H pylori was detected by the use of monoclonal antibody. Helicobacter pylori were identified in gastric brushings by a monoclonal antibody in 8 out of 10 pigs and 7 out of 10 rabbits. This study suggests an animal reservoir of Helicobacter pylori which may be of importance in human infection.

Animals↗
PubMed1991

Postnatal transmission of human immunodeficiency virus type 1 from mother to infant. A prospective cohort study in Kigali, Rwanda.

BACKGROUND: Although transmission of human immunodeficiency virus type 1 (HIV-1) from mother to infant has been well documented during pregnancy and delivery, little is known about the possible transmission of HIV-1 during the postnatal period. METHODS: We conducted a prospective cohort study in Kigali, Rwanda, of 212 mother-infant pairs who were seronegative for HIV-1 at delivery. All the infants were breast-fed. The subjects were followed at three-month intervals, with Western blot assays for antibodies to HIV-1 and testing of mononuclear cells by a double polymerase chain reaction (PCR) using three sets of primers. To evaluate potential risk factors, each mother who seroconverted was matched with three seronegative control women. RESULTS: After a mean follow-up of 16.6 months, 16 of the 212 mothers became seropositive for HIV-1. Of their 16 infants, 9 became seropositive. One infant was excluded from the analysis because of a positive test by PCR on the blood sample obtained at birth. Postnatal seroconversion to HIV-1 occurred in four of the five infants born to the mothers who seroconverted during the first 3 months post partum, and in four infants of the 10 mothers who seroconverted between month 4 and month 21. In all cases, the infant seroconverted during the same three-month period as the mother. The main risk factor for maternal seroconversion was being single. CONCLUSIONS: HIV-1 infection can be transmitted from mothers to infants during the postnatal period. Colostrum and breast milk may be efficient routes for the transmission of HIV-1 from recently infected mothers to their infants.

Base Sequence↗
PubMed1991

Helicobacter pylori in children with peptic ulcer and their families.

Little is known about the source and spread of Helicobacter pylori, but transmission from infected family contacts has been suggested. We have therefore investigated 15 children with peptic ulcer and their first-degree relatives for H. pylori. Serum anti-H. pylori IgG, pepsinogen I, and gastrin levels were measured. Endoscopy was carried out on the children and relatives, and biopsies were taken from the gastric antrum for histology, microbiology, and urease testing. Six of 11 children with duodenal ulcer (55%) and two of four children with gastric ulcer (50%) were positive for H. pylori. Fourteen of 16 parents (87%) and eight of 13 siblings (61%) of H. pylori-positive children with peptic ulcer were also infected compared with eight of 14 parents (57%) and none of four siblings of H. pylori-negative children with peptic ulcer (P less than 0.10, greater than 0.05, and NS, respectively). The children with H. pylori-negative peptic ulcer and negative siblings combined were younger than positive children with peptic ulcer and positive siblings (P less than 0.001). The reliability of serum anti-H. pylori IgG level as a screening test for infection was confirmed. These findings call into question a pathogenetic role for H. pylori in some childhood peptic ulceration, but do suggest that person-to-person spread of infection occurs.

Adolescent↗