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Biomedical subjects

A Toma

Publications and source records attributed to A Toma.

At least 19 recordsLinked to original sources
PubMed2006

Carbon monoxide dissociation on Rh nanopyramids.

CO dissociation on rhomboidal faceted nanopyramids, produced on Rh(110) by fine-tuning of ion irradiation conditions, has been studied by high resolution core-level spectroscopy. We find that this morphology presents a large efficiency towards CO dissociation, a process which is inhibited on flat (110) terraces. We also measured the reactivity of nanostructures bound by different artificial step distributions identifying the sites responsible for the molecular bond disruption in the undercoordinated (n=6) edges running along the [11[over ]2] equivalent directions, with CO sitting in on-top configuration.

Journal Article↗
PubMed2005

Monoclonal antibody A7-superparamagnetic iron oxide as contrast agent of MR imaging of rectal carcinoma.

Superparamagnetic iron oxide (SPIO)-based colloid has been used clinically as a tissue-specific magnetic resonance contrast agent. We coupled monoclonal antibody A7 (Mab A7), which reacts specifically with human colorectal carcinoma, to Ferumoxides (SPIO) and examined the accumulation of this conjugate in xenografted tumours in nude mice. We examined in vitro immunoreactivity of Mab A7 coupled to Ferumoxides and its in vivo distribution in nude mice with human colorectal carcinoma. Magnetic resonance imaging of tumour-bearing nude mice was performed 72 h after injection of A7-Ferumoxides. A7-Ferumoxides retained binding activities that were nearly identical to intact Mab A7. More of the radiolabelled A7-Ferumoxides accumulated in the tumour than normal mouse IgG-Ferumoxides from 12 h onwards after injection (P<0.05). Both A7-Ferumoxides and normal mouse IgG-Ferumoxides disappeared from blood linearly over time. The accumulation levels in normal tissue decreased linearly over time but were lower than levels in tumours from 6 h. In magnetic resonance T2-weighted imaging of the tumour-bearing nude mice, signal intensity was reduced at the margin of the tumour by injection of A7-Ferumoxides. Mab A7 coupled to Ferumoxides is potentially suitable as a magnetic resonance contrast agent for detecting local recurrence of rectal carcinoma.

Animals↗
PubMed2005

Advice given to patients with epistaxis by A&E doctors.

This study was devised to determine the proportion of patients with epistaxis seen in accident and emergency (A&E) departments and discharged with verbal/written advice, and to examine if this information affects re-attendance rates. A questionnaire was given to all A&E doctors probing their current practice regarding advice given to patients with epistaxis on discharge. The information was complemented with a case note audit of patients with epistaxis seen and discharged by A&E doctors over a 2 month period, which assessed the content and format of advice given and the number of re-attendances. The standard used stated that all patients discharged from A&E should be given both verbal and written advice regarding the prevention and management of further bleeds. The A&E doctors were then invited to a presentation on the management of epistaxis and the appropriate advice to give patients on discharge. Written advice leaflets on the prevention and management of further bleeds were placed in the A&E department and were accessible to doctors and patients. Case notes were re-audited over the following 2 month period. Verbal and written advice increased from 19% to 61% and 2% to 54% respectively. The number of re-attenders who had previously only seen A&E doctors was reduced from 11 (17%) in the first half to 5 (8%) in the second half of the cycle, representing a 9% reduction. We conclude that the provision of adequate verbal and written advice to patients with epistaxis may have an important role in the prevention of further bleeds and subsequent re-attendance to A&E departments.

Adolescent↗
PubMed2001

[Effect of monoclonal antibody-neocarzinostatin conjugate for gastric cancer with peritoneal dissemination--comparison between early and late administration].

A7-NCS, which is a conjugate of the monoclonal antibody A7 against a human colonic cancer and the anticancer agent neocarzinostatin (NCS), reacts with human gastric cancers at a high rate. The anticancer effect of A7-NCS is stronger than that of free NCS. Nude mice models of peritoneal dissemination were established simply by intra-peritoneal inoculation of the antigen-positive human gastric cancer cell line MKN45. Using these models, the anticancer effect of A7-NCS against the peritoneal dissemination of gastric cancer was examined. The murine peritoneal dissemination models were divided into three groups. The anticancer effect of the group injected intra-peritoneally with A7-NCS 2 days after cancer inoculation was compared with that injected 18 days after inoculation. The anticancer effect in the 18-day group was inferior to that in the 2-day group, but was superior to that in the non-treated group. To get a better result in the 18-day group, which is in the advanced stage of peritoneal dissemination, repeated injection and the dose of A7-NCS should be examined.

Animals↗
PubMed2001

[Usefulness of local administration of methotrexate bound to activated carbon particles (MTX-CH)].

We developed a new dosage formulation, methotrexate bound to activated carbon particles (MTX-CH), and used it to reduce tumors via its long-acting effect at the administration sites. MTX-CH was injected locally into tumors on the back of BALB/c mice, 30 mg/mouse, as MTX and compared with mice treated with MTX aqueous solution, saline solution, activated carbon particles (CH-40) and non-treated mice. The MTX concentration at the administration sites was higher in the MTX-CH group than in the MTX aqueous solution group. A marked effect on the control of tumor growth by MTX-CH was noted after repeated administration (every 3 days, total 4 times) throughout the observation period. Although tumor size was not reduced, necrosis was microscopically observed around the site of MTX-CH administration. For the reasons mentioned above, MTX-CH is superior to MTX aqueous solution in terms of long-acting effect at the administration sites and the control of tumor growth.

Animals↗
PubMed2000

Outcome of prophylactic radical lymphadenectomy with gastrectomy in patients with early gastric carcinoma without lymph node metastasis.

BACKGROUND: Prophylactic extended lymphadenectomy with gastrectomy may prolong survival in patients with early gastric carcinoma without lymph node metastasis. However, the therapeutic value of extensive lymphadenectomy in patients with early gastric carcinoma remains controversial. METHODS: The authors retrospectively analyzed 423 patients with early gastric carcinoma without lymph node metastasis who underwent gastrectomy and did not die of other diseases to evaluate the effect of prophylactic extended lymphadenectomy on postoperative survival. The postoperative survival rate of patients who underwent prophylactic extended lymphadenectomy was compared with that of patients who underwent prophylactic limited lymphadenectomy. RESULTS: Although extended lymphadenectomy did not appear to improve the postoperative survival rate of patients with mucosal tumors, it did improve the postoperative survival rate of patients with submucosal tumors. Whether prophylactic extended lymphadenectomy was performed significantly affected outcome in patients with early gastric carcinoma who had submucosal tumors without regional lymph node metastasis. CONCLUSIONS: Extensive lymphadenectomy with gastrectomy should be performed to prolong the survival of the patients with submucosal tumors.

Aged↗
PubMed2000

Long-term benefit of extended lymphadenectomy with gastrectomy in distally located early gastric carcinoma.

BACKGROUND: Extended lymphadenectomy performed with gastrectomy has been reported to prolong survival of patients with early gastric cancer. However, some authors question the value of extensive lymphadenectomy in these patients, especially since much recent discussion of patient quality of life after gastrectomy has favored less invasive operations. METHODS: We retrospectively analyzed 485 patients who had undergone gastrectomy for early cancer in order to evaluate the effect of extended versus limited lymphadenectomy on postoperative survival. Various prognostic factors were examined for patients whose tumors were located in the distal third of the stomach. RESULTS: Although extended radical lymphadenectomy did not prolong postoperative survival when early gastric cancer was located in the middle or proximal third of the stomach, it did when the tumor occupied the distal third. CONCLUSIONS: Performance of extended radical lymphadenectomy was a significant prognostic factor for early gastric cancer patients when tumors were located in the distal third of the stomach.

Female↗
PubMed1999

Serum antibodies anti-H. pylori and anti-CagA: a comparison between four different assays.

The authors compare efficacy of two ELISA assays (one supplied by DIAMEDIX [Delta Biological s.r.l.], and the other by RADIM [RADIM I]) in detecting total anti-H. pylori antibodies, and of two further ELISA methods (one supplied by EUROSPITAL [Helori CTX IgG] and the other by RADIM [RADIM 2]) in identifying anti-CagA antibodies, using sera from 69 controls (20 adults and 49 children) and from 96 patients, obtained before endoscopy. Seventy-three of the patients had H. pylori infection, while the remaining 23 were H. pylori negative (histology and polymerase chain reaction [PCR]). Fifty-two of the H. pylori positive patients, had cagA-positive strain infection, identified by PCR. The DIAMEDIX assay was found to be more sensitive (92%) than RADIM 1 (79%) in identifying H. pylori positive patients, irrespective of the infecting strain. On the other hand, the DIAMEDIX assay was less specific than RADIM 1 for H. pylori-negative patients (43% vs. 83%). However, when patients already treated for H. pylori infection were excluded from the group of H. pylori-negative patients, the DIAMEDIX assay had a specificity of 89%. In identifying anti-CagA antibodies, the kit supplied by RADIM (RADIM 2) had a sensitivity of 90% and a specificity of 94%, whereas that supplied by EUROSPITAL had a sensitivity of 100% and a specificity of 76%. The performances of the two methods in the identification of anti-CagA antibodies were found to be similar. The authors conclude that, in view of its high sensitivity, the DIAMEDIX assay may be useful in screening for H. pylori infection.

Adolescent↗
PubMed1999

Polymorphonuclear oxidative burst after Helicobacter pylori water extract stimulation is not influenced by the cytotoxic genotype but indicates infection and gastritis grade.

H. pylori-associated gastric mucosal inflammation is characterized by the presence of polymorphonuclear (PMN) leukocyte infiltrate, which is more severe when the infecting strain is cagA positive. After appropriate stimuli, such as bacterial products, PMN release large amounts of oxygen derived free radicals and proteases, to kill the bacterium. H. pylori seems to be particularly resistant to the oxidative machinery of PMN, which can in turn damage the host gastric mucosa. We evaluated peripheral PMN oxidative burst response after stimulation with water extracts from cagA positive (WEcagA+) or negative (WEcagA-) H. pylori strains in infected (n=31) and non-infected patients (n=32) in comparison with healthy controls (n=16); the influence of gastric mucosal inflammatory infiltrate and activity grade on PMN oxidative burst were also assessed. PMN oxidative burst was measured by FACS analysis. H. pylori water extracts were obtained from bacterial culture. H. pylori genotype was determined by means of the polymerase chain reaction. The PMN oxidative burst in H. pylori infected patients was significantly higher than that in H. pylori negative or healthy controls, no differences being found when the results following WEcagA+ and WEcagA- stimulation were compared. The difference in PMN oxidative burst obtained after WEcagA- and E. coli (standard stimulus for PMN oxidative burst) stimulation discriminated H. pylori infected from non-infected patients with a sensitivity of 90% and a specificity of 97%. The grade of PMN oxidative burst correlated with PMN infiltration grade of the gastric mucosa. Our findings allow to conclude that PMN oxidative burst activation by H. pyloriWE is species- but not strain-correlated. PMN priming, probably consequent to the action of soluble mediators released by mononuclear cells, makes PMN hyper-responsive to H. pylori products, thus favoring the release in the gastric mucosa of infected patients of large amounts of oxygen-derived free radicals, which are not enough to eliminate the infection, but may contribute to damaging the gastric mucosa itself. Peripheral PMN oxidative burst response to H. pyloriWE might furthermore be of help in diagnosing H. pylori infection.

Adult↗
PubMed1999

[Biochemical markers of gastric functioning].

The serum determination of pepsinogen A (PGA) and pepsinogen C (PGC) might indicate gastric mucosal inflammation and atrophy. Body gastric mucosa produces both PGA and PGC, while antral mucosa produces only PGC. Therefore, diseases involving mainly the antrum, such as H. pylori infection, are mainly indicated by the variations in serum PGC than in serum PGA. In agreement, when the antral mucosa is infected by the more virulent cagA positive H. pylori strains, which cause severe inflammation, serum PGC significantly increases. Another indirect indicator of gastric inflammation is polymorphonuclear (PMN) oxidative burst after the stimulation with water extracts from H. pylori culture: this parameter is significantly increased in infected if compared to non-infected subjects. The higher oxidative burst response of peripheral PMN in infected patients, possibly consequent to the release of specific cytokines able to prime PMN towards H. pylori products, is unable to eliminate the infection, but it might concur in damaging the gastric mucosa.

Biomarkers↗
PubMed1999

Questionnaire survey and prevalence of intestinal helminthic infections in Barru, Sulawesi, Indonesia.

A questionnaire survey with parasitological study was carried out on the inhabitants of 4 villages in Barru district, Sulawesi, Indonesia from 1994 to 1995. The questionnaire dealt with life style and sanitary conditions. In 482 houses in the 4 villages, interviews for the items of the questionnaire were conducted with the owner, housekeeper and children of the same family. In Pancana and Lalolang, 37.7% and 50% respectively of man inhabitants surveyed were fishermen, while in Lompo Riaja and Pattappa, 38.6% and 65.5% respectively were farmers. The highest proportion of official workers was 33.7% in Lompo Riaja. Educational level was low; 88.4% in Pancana, 90.4% in Lalolang, 62.1% in Lompo Riaja and 91.2% in Pattappa had elementary or below elementary school education. In Lompo Riaja, 30.8% of the inhabitants graduated from senior high school or university. The percentage of families having their own latrine was 30.3% in Pancana, 13.2% in Lalolang, 31.9% in Pattapa and 60% in Lompo Riaja. The people without latrines usually defecated in rice fields, seaside or riverside. A total of 654 fecal samples was examined by the modified Kato-Katz thick smear method. Five nematode species, Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Strongyloides stercoralis and unidentified Rhabditoids of free-living nature were detected. Cestode, Hymenolepis nana infection was confirmed. All the hookworms examined by the modified Harada-Mori culture technic were Necator americanus. Trichuris infection was most common, followed by hookworm and Ascaris infections, both in young (aged 4-14) and older (aged over 15) age groups. The prevalence of hookworm infection was significantly higher in males than in females of older age. Among the older age group, the prevalence of Trichuris infection was significantly lower in Lompo Riaja, while hookworm infection was the highest in Pattappa. Among all the inhabitants examined for parasite infection, 17.4% had 3 kinds of nematode, Ascaris, Trichuris and hookworm. However, egg counts revealed that most of the inhabitants with Trichuris or hookworm had light infections. The inhabitants with higher education background had significantly lower infection rates of Ascaris and Trichuris. The prevalence of hookworm infection was not significantly different between the inhabitants owning latrine and without it, but the prevalence of Ascaris and Trichuris, differed significantly.

Adolescent↗
PubMed1998

Analysis of Helicobacter pylori vacA and cagA genotypes and serum antibody profile in benign and malignant gastroduodenal diseases.

BACKGROUND: Helicobacter pylori species comprise different strains, cytotoxic and non-cytotoxic, which can be identified on the basis of their genomic pattern. AIMS: (1) To evaluate the polymorphism of the vacA gene and to ascertain whether the cagA gene is present in patients with gastric adenocarcinoma. (2) To study the anti-H pylori antibody profile using western blotting. PATIENTS: Twenty one patients with gastric adenocarcinoma and 71 with H pylori associated benign disease (nine gastric ulcer, 29 duodenal ulcer, 25 antral gastritis, and eight duodenitis). METHODS: The polymerase chain reaction was used to verify the presence or absence of cagA and to study the polymorphism of vacA in gastric mucosal samples obtained during endoscopy for patients with benign diseases and at surgery for patients with gastric adenocarcinoma. Fasting sera were used to assess anti-H pylori antibodies against different H pylori antigens by western blotting. RESULTS: CagA gene and the allele s1 of vacA were significantly less frequent in patients with antral gastritis (60% and 60%) compared with patients with gastric adenocarcinoma (94% and 100%) and with other non-malignant gastroduodenal diseases (93% and 87%) (chi 2 = 16.01, p < 0.001; and chi 2 = 13.97, p < 0.01). In patients with gastric adenocarcinoma, antibodies against a 74 kDa H pylori antigen were less frequently found than in patients with benign diseases. CONCLUSIONS: H pylori infection caused by cagA positive/vacA s1 strains is a frequent finding in patients with gastric adenocarcinoma. Prospective studies are needed to confirm whether the low incidence of positive serological response to the 74 kDa H pylori antigen in patients with gastric adenocarcinoma is important.

Adenocarcinoma↗
PubMed1996

Serum pepsinogen C: a useful marker of Helicobacter pylori eradication?

Medical treatment for Helicobacter pylori (Hp) infection is now recommended in several types of gastroduodenal disease, and its success is usually monitored by hystology. The end-points of our work were to identify the most suitable serum index of Hp eradication among pepsinogen A (PGA), pepsinogen C (PGC), PGA/PGC ratio, gastrin, and IgG anti-Hp (IGG). We studied a total of 289 Hp positive (Giemsa staining) patients, who were treated with 40 mg/day omeprazole (140 cases) or with 480 mg/day bismuth subsalicylate (149 cases) for 4 weeks. All the patients also received 1 g/day metronidazole + 2 g/day amoxycillin for the first 2 weeks of treatment. Two months after the end of therapy, the patient underwent a second endoscopy and Hp histological assessment: the infection was eradicated in 192 and still present in the remaining 97 subjects. Gastrin, PGA, PGC, and IGG were measured before and after therapy. All indices significantly decreased after therapy in eradicated patients, while PGA and gastrin significantly decreased after therapy in both eradicated and noneradicated patients, although in the latter group the variations were less pronounced. We calculated the per cent decrease of the studied indices. PGC, with a decrease of more than 25%, was found to be the most accurate biochemical index. Variation in PGC levels before and after treatment were correlated with corresponding variations in Hp bacterial load. In conclusion, between the different biochemical parameters evaluated, PGC showed the highest clinical efficiency.

Adult↗
PubMed1996

Helicobacter pylori infection enhances mucosal interleukin-1 beta, interleukin-6, and the soluble receptor of interleukin-2.

It is thought that Helicobacter pylori colonization of the gastric mucosa might stimulate the production of several cytokines, which might trigger and maintain the gastric inflammation associated with Helicobacter pylori infection. In the present study we evaluated interleukin-1 beta. interleukin-6, and the soluble receptor of interleukin-2 both in mucosal homogenates and in the sera of Helicobacter pylori-infected (39 cases) and uninfected (40 cases) patients to investigate whether there was any relationship between variations in cytokines and (1) the severity of Helicobacter pylori-associated gastritis or (2) CagA-positive Helicobacter pylori strains. Mucosal, but not serum levels of interleukins-1 and -6 and interleukin-2 receptor were significantly higher in infected than uninfected patients. Serum levels of Helicobacter pylori antibodies were significantly higher in infected than uninfected patients. These levels correlated with mucosal interleukin-1 beta. The degree of antral or body inflammatory grade was higher in infected than in uninfected patients; cytokines levels were higher in patients with high-grade gastritis, most of whom were Helicobacter pylori positive. Patients infected with CagA-positive strains also had higher levels of interleukin-1 beta, but not of interleukin-2 receptor or interleukin-6. In conclusion. Helicobacter pylori infection results in a local increase in interleukins-1 beta and -6 and interleukin-2 receptor associated with high-grade mucosal inflammation. Interleukin-1 beta seems to favor anti-Helicobacter pylori antibody production, and mucosal levels are enhanced mainly in patients infected with cytotoxic Helicobacter pylori strains.

Adult↗
PubMed1996

Middle ear barotrauma in patients undergoing hyperbaric oxygen therapy.

Hyperbaric oxygen therapy is associated with a risk of barotrauma to the middle ear. This prospective study of 82 patients undergoing long-term therapy for chronic conditions was designed to measure the incidence and severity of middle ear barotrauma. Twenty-four patients (29.3%) required the insertion of ventilation tubes for otalgia, significantly more of whom were suffering from radionecrosis of the head and neck region (P < 0.01). Thirty-two of the remaining 58 patients (55%) underwent specialist ENT assessment by otoscopy and tympanometry. Five ears (8%) showed the otoscopic changes of barotrauma (TEED grade 3 or 4), and one ear (2%) showed tympanometric evidence of a middle ear effusion (Type B tympanogram). We conclude that despite careful tuition in pressure equalization and the appropriate use of ventilation tubes, up to 8% of ears sustain significant barotrauma. Tympanometry is unreliable in detecting these changes, otoscopy provides the most reliable screening technique.

Aged↗
PubMed1996

Gastric juice polymerase chain reaction: an alternative to histology in the diagnosis of Helicobacter pylori infection.

BACKGROUND: Infection from Helicobacter pylori plays a role in several gastroduodenal diseases. The recent availability of molecular techniques, particularly the polymerase chain reaction (PCR), allows us to detect small amounts of this bacterium. The aims of this study were to compare PCR and histological findings and to ascertain the clinical usefulness of H. pylori PCR identification in different biological samples. MATERIALS AND METHODS: We studied 94 consecutive patients. Saliva, gastric juice, and four antral and four body biopsies were obtained from each patient. H. pylori was evaluated histologically in two antral and two body biopsies (Giemsa or Warthin-Starry stain). After extraction, DNA was submitted for PCR amplification using the two primers HPU1 and HPU2, which amplified a 411-bp product from the urease gene A. RESULTS: Forty-nine patients were H. pylori-positive at histological workup. The sensitivity of PCR was 92% for gastric juice, 73% for antral biopsies, 61% for body biopsies, and 13% for saliva. Of the 45 H. pylori-negative patients at histological assessment, 7 (16%) had positive findings on PCR, mainly when gastric juice was examined. CONCLUSIONS: These results indicate that PCR is as sensitive as histological assessment. We suggest that PCR H. pylori detection in gastric juice is a sensitive method for diagnosing this infection.

Adult↗
PubMed1996

Helicobacter pylori serology in patients with chronic gastritis.

OBJECTIVES: Helicobacter pylori (Hp) infection is known to cause several gastroduodenal diseases. In patients with non-ulcer dyspepsia, we assessed the link between Hp infection and gastric mucosal inflammation, as well as the influence of Hp and inflammation on the serum levels of anti-Hp antibodies (IgG), pepsinogen A (PGA), pepsinogen C (PGC), and gastrin. METHODS: Entering the study were 221 patients with non-ulcer dyspepsia, all of whom underwent upper gastrointestinal endoscopy. RESULTS: Of the 221 patients investigated, 135 (61%) were Hp positive. The higher the bacterial load, the worse the associated gastritis, the gastric antrum and body being considered. All of the serological indices studied were found to be influenced by gastritis. Serum IgG satisfactorily discriminated between Hp-positive and Hp-negative subjects, with a sensitivity of 84% and a specificity of 86%. PGC, PGA, and gastrin were less accurate. Only PGC only found to be correlated with Hp load. The product of IgG and PGC improved the diagnostic accuracy of IgG alone. CONCLUSIONS: Hp infection, frequently found in patients with non-ulcer dyspepsia, is associated with gastric mucosal inflammation; of the indices studied, serum IgG and PGC most accurately indicated Hp infection, and their product may be proposed as an aid in diagnosing Hp infection in dyspeptic patients.

Adult↗