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Biomedical subjects

A Rotenberg

Publications and source records attributed to A Rotenberg.

At least 19 recordsLinked to original sources
PubMed2001

Cytokeratin immunoreactivity of intestinal metaplasia at normal oesophagogastric junction indicates its aetiology.

BACKGROUND AND AIMS: Cytokeratin (CK) 7 and 20 patterns are specific for long and short segments of Barrett's oesophagus but their use has not been assessed in intestinal metaplasia arising in macroscopically normal gastro-oesophageal junction (GOJ). PATIENTS AND METHODS: This study was carried out in a large prospective series of 254 patients who underwent upper endoscopy, had normal gastro-oesophageal anatomy, and who had biopsies of the antrum, fundus, cardia, GOJ, and lower oesophagus. Intestinal metaplasia of the GOJ was typed by histochemistry with high iron diamine-alcian blue staining and by immunohistochemistry using CK7 and CK20 antibodies. Results were correlated with clinical, endoscopic, and pathological data. RESULTS: Sixty (23.6%) of our patients presenting with a normal GOJ had intestinal metaplasia. The CK7/CK20 pattern identified two groups of patients: one highly correlated with Barrett's and the other with characteristics of Helicobacter pylori gastritis. The Barrett's type CK7/CK20 pattern was related to a high frequency of gastro-oesophageal reflux symptoms (p<0.02) and normal endoscopic appearance of the stomach (p<0.03). In contrast, the gastric type CK7/CK20 pattern was linked to atrophic (p<0.02) or erythematous (p<0.05) appearance of the stomach (p<0.03), high frequency of H pylori infection (p<0.04), antral inflammation (p<0.006) with atrophy (p<0.02), and intestinal metaplasia (p<0.02). CONCLUSION: In patients presenting with intestinal metaplasia in normal appearing GOJ, the cytokeratin pattern identifies two groups of patients, one with features identical to those of long segment Barrett's oesophagus and one with features seen in H pylori gastritis. These data may be used by clinicians and should result in improved endoscopic surveillance strategies targeted specifically at patients at increased risk of Barrett's oesophagus and thus cancer.

Adolescent↗
PubMed2000

Parallel instabilities of long-term potentiation, place cells, and learning caused by decreased protein kinase A activity.

To further elucidate the links among synaptic plasticity, hippocampal place cells, and spatial memory, place cells were recorded from wild-type mice and transgenic "R(AB)" mice with reduced forebrain protein kinase A (PKA) activity after introduction into a novel environment. Place cells in both strains were similar during the first exposure and were equally stable for recording sessions separated by 1 hr. Place cell stability in wild-type mice was unchanged for sessions separated by 24 hr but was reduced in R(AB) mice over the longer interval. This stability pattern parallels both the reduced late-phase long-term potentiation in hippocampal slices from R(AB) mice and the amnesia for context fear conditioning seen in R(AB) mice 24 but not 1 hr after training. The similar time courses of synaptic, network, and behavioral instability suggest that the genetic reduction of PKA activity is responsible for the defects at each level and support the idea that hippocampal synaptic plasticity is important in spatial memory.

Action Potentials↗
PubMed1997

Variable place-cell coupling to a continuously viewed stimulus: evidence that the hippocampus acts as a perceptual system.

A key feature of perception is that the interpretation of a single, continuously available stimulus can change from time to time. This aspect of perception is well illustrated by the use of ambiguous figures that can be seen in two different ways. When people view such a stimulus they almost universally describe what they are seeing as jumping between two states. If it is agreed that this perceptual phenomenon is causally linked to the activity of nerve cells, the state jumps would have to occur in conjunction with changes in neural activity somewhere in the nervous system. Our experiments suggest that hippocampal place cells are part of a perceptual system. We conducted variations of a 'cue-card rotation' experiment on rats in which the angular position of a prominent visual stimulus on the wall of cylinder is changed in the rat's presence. The three main results are that (i) place-cell firing fields remain stationary if the cue is rotated by 180 degrees, so the relation between the cue and the field is altered; (ii) firing fields rotate by 45 degrees when the cue is rotated by 45 degrees, so the relation between the field and the card is maintained; and (iii) if the cue is first rotated by 180 degrees and then rotated in a series of 45 degrees steps, the field winds up at a different angular position relative to the card when the card is back in its original position. Thus, place cells can fire in two different ways in response to a continuously viewed stimulus. We conclude that place cells reveal that the hippocampal mapping system also has properties expected of a perceptual system.

Animals↗
PubMed1997

Reasons for student attrition on nursing courses: a study.

Student attrition (dropping out) wastes time and resources which schools of nursing can ill afford. This study from Israel sets out to identify the reasons for student attrition and finds that academic failure is only one factor. The authors suggest some ways in which high risk students can be identified and helped.

Education, Nursing, Baccalaureate↗
PubMed1997

Young people considering nursing as a career: starters vs. non-starters.

This study focused on applicants who were accepted to a nursing education program but did not begin their studies, thus wasting time, effort and money. Of 953 accepted applicants, 27% did not enter the program. Significant variables differentiating starters from non-starters were higher psychometric score, higher paternal education, lower priority for nursing studies, older age, non-Israeli country of birth and not completed army service. The study relating to starters vs. non-starters is one aspect of a large study (Ehrenfeld, Rotenberg, Sharon, & Bergman, 1995). In most nursing education programs the number of applicants exceed the faculty's capacity, and suitable candidates must be rejected. It is therefore both wasteful and disappointing when accepted applicants change their mind and do not actually begin in the program. In light of the costs and complexities involved in the student screening process and the continuous efforts extended today all over the world to raise the standards of nursing education and care, the factors differentiating starters from non-starters may have important implications. The aim of the present study was to evaluate the screening process at the Tel Aviv University baccalaureate nursing program and determine which variables were predictive of starters and non-starters among accepted applicants.

Discriminant Analysis↗
PubMed1996

Mice expressing activated CaMKII lack low frequency LTP and do not form stable place cells in the CA1 region of the hippocampus.

To relate different forms of synaptic plasticity to the formation and maintenance of place cells in the hippocampus, we have recorded place cells in freely behaving, transgenic mice that express a mutated Ca2+-independent form of CaM Kinase II. These mice have normal long-term potentiation (LTP) at 100 Hz, but they lack LTP in response to stimulation at 5-10 Hz and are impaired on spatial memory tasks. In these transgenic mice, the place cells in the CA1 region have three important differences from those of wild types: they are less common, less precise, and less stable. These findings suggest that LTP in the 5-10 Hz range may be important for the maintenance of place-field stability and that this stability may be essential for the storage of spatial memory.

Action Potentials↗
PubMed1996

Helicobacter pylori infection in patients with Barrett's oesophagus: a prospective immunohistochemical study.

The prevalence of Helicobacter pylori infection in patients with Barrett's oesophagus was studied prospectively. A sensitive immunohistochemical staining of H pylori was performed in oesophageal and gastric biopsies of 73 patients from a surveillance group with this condition. H pylori was detected in 11 cases of Barrett's mucosa (15%) and in 26 gastric mucosa specimens (35.6%). All cases positive in Barrett's mucosa were also positive in the stomach. In Barrett's oesophagus, H pylori was never found on specialised epithelium. The percentage of Barrett's mucosa showing inflammatory changes was similar in specimens with and without H pylori, both for chronic (81% v 79%) and acute (9% v 10%) infiltrates. These results indicate that H pylori infection does not play an aetiological role in Barrett's oesophagus and that colonisation of the metaplastic mucosa by this bacteria is related with the presence of gastric type mucosa in the oesophagus and of H pylori infection in the stomach.

Adult↗
PubMed1996

[Are lymphocytic and collagenous colitis two forms of a single disease? Arguments taken from a biopsy quantitative study].

Collagenous colitis and lymphocytic colitis are defined by a clinicopathologic syndrome with chronic watery diarrhea, microscopic lesions of colonic biopsies, and normal barium enema and colonoscopy. A histopathological study was performed on multiple colorectal biopsies to compare 12 cases of collagenous colitis (defined by a subepithelial collagen thicker than 10 microns) and 7 cases of lymphocytic colitis (defined by a number of intraepithelial lymphocytes more than 20 per 100 epithelial cells at least in one biopsied site). The study included a semiquantitative analysis of inflammatory infiltrate in the lamina propria, crypts distortion and epithelial detachment. The number of intraepithelial lymphocytes per 100 epithelial cells was determined in surface epithelium and crypts. The subepithelial collagen thickening was studied by computerised morphometry. The intraepithelial lymphocytes, villous atrophy and thickness of the subepithelial collagen were also determined in gastric and duodenal biopsies. In collagenous colitis, the subepithelial collagenous thickness ranged from 10 to 40 microns in the colon (median 20.99 microns). In 4 cases of collagenous colitis, no thickening of the collagen plate was seen in the rectum. We found constant epithelial detachment and mucosal distortion. In lymphocytic colitis, the thickness of the subepithelial collagen ranged from 6 to 10 microns in 4 cases and was less than 6 microns in 3 cases (median 6.24 microns). The median number of intraepithelial lymphocytes in surface epithelium was 22.35 (range 18.2 to 40) in lymphocytic colitis versus 12.22 (range 4.6 to 24.4) in collagenous colitis. In conclusion, we observed an overlap of both the collagenous plate thickness and the number of intraepithelial lymphocytes in collagenous colitis and lymphocytic colitis. This result favours a unified histogenesis for these two entities.

Colitis↗
PubMed1995

Multicentre prospective controlled study of Barrett's oesophagus and colorectal adenomas. Groupe d'Etude de l'Oesophage de Barrett.

Previous studies have suggested that patients with Barrett's oesophagus may be at increased risk of colorectal neoplasia, though the association is disputed. In a multicentre prospective study we compared the prevalence of colorectal adenomas in patients with Barrett's oesophagus and controls. Barrett's oesophagus patients (n = 104) had histological confirmation of columnar epithelium extending more than 3 cm above the gastro-oesophageal junction. The 537 controls were patients with symptoms suggesting irritable bowel syndrome. No participant had a personal history of colonic neoplasm. Each patient underwent colonoscopy. Histologically proven adenomas were found in 26 Barrett's patients (25%) and 75 controls (14%). Three colorectal cancers were discovered in each group. The prevalence of adenomas was greater in the Barrett's oesophagus group than in the control group (p < 0.01) but the relation became non-significant after adjustment for age and sex and control for other known risk factors by a logistic regression model (odds ratio 1.4 [0.7-2.7]). The relative risk of adenoma was significantly higher in patients older than 59 than in younger patients (2.2 [1.3-3.5]) and in men than in women (3.4 [2.0-5.7]). Other factors contributing significantly to the risk of adenoma were a family history of colorectal cancer (2.3 [1.1-4.8]), rectal bleeding (2.1 [1.1-3.9]), previous colonic investigation (0.3 [0.1-0.7]), and complete as opposed to partial colonoscopy (6.4 [0.8-48.3]). We conclude that Barrett's oesophagus is not an independent risk factor for colorectal neoplasia and, therefore, is not, in itself an indication for colorectal screening.

Adenoma↗
PubMed1990

[Human chronic gastritis associated with non-Helicobacter pylori spiral organisms (Gastrospirillum hominis). Four cases and review of the literature].

Four cases of human active chronic gastritis associated with Gastrospirillum hominis, a recently described spiral shaped organism are presented. These 4 cases originated from a series of 1976 consecutive gastric biopsies, i.e. a prevalence of 0.25 percent in our material, are compared with Helicobacter pylori prevalence of 45 percent. Histopathological findings were chronic active gastritis with mild or no atrophy. Electron microscopy showed spiral bacteria with terminal flagellae, identical to those previously described in the literature. These bacteria have not yet been cultured; similar organisms are found in many animal species, and it seems that they do not provoke gastric inflammation. Gastrospirillum hominis could be responsible for cases of Helicobacter pylori negative chronic gastritis in man, but its pathogenicity remains to be demonstrated.

Adult↗
PubMed1989

Treatment of duodenal ulcer with rioprostil: a randomized multicentre double-blind study.

The effectiveness of rioprostil, 300 micrograms b.d. is evaluated in evolutive duodenal ulcer in a double-blind study in five French and North African centres. A total of 115 patients are included in the study (57 in the rioprostil group and 58 in the placebo group). After a 4-week treatment period, a significantly higher endoscopic healing rate is observed in the rioprostil group (57%) compared with the placebo group (33%) (p less than 0.01). The mean time with abdominal pain is significantly lower in the rioprostil group (5.6 +/- 4.4 days) compared to the placebo group (12.7 +/- 5 days) (p less than 0.001). Clinical and biological tolerance is excellent. The only side effect is diarrhoea (3.5% in the rioprostil group). In only one case does diarrhoea necessitate cessation of treatment. Rioprostil, 300 micrograms b.d., is thus effective in the treatment of developing duodenal ulcer.

Anti-Ulcer Agents↗
PubMed1984

[Treatment of duodenal ulcer outbreak with omeprazole. Results of a multicenter non-controlled study].

Sixty-one patients with symptomatic endoscopically confirmed duodenal ulcer, 5 mm or more in diameter, were treated with omeprazole 30 mg once daily in the morning for 4 weeks. Complete ulcer healing was assessed by endoscopy performed after 15 and, if necessary, 29 days of treatment. The healing rate as 83 p. 100 (49/59 patients) after 2 weeks, and 98 p. 100 (58/59 patients) after 4 weeks. Only 5 patients remained symptomatic on day 15. Fifty-six patients did not take any antacid during the course of treatment. There were few adverse effects. No clinically significant changes in laboratory parameters were observed. These results confirm: the remarkable efficiency of omeprazole in short-term treatment of duodenal ulcer, the good tolerance to this drug, at least in short duration treatment.

Adult↗