Helicobacter pylori and precancerous conditions of the stomach: The frequency of infection in a cross-sectional study of 79 consecutive patients with chronic antral gastritis in Yaoundé, Cameroon

Introduction: The study aimed at determining the different types of precancerous conditions of the stomach and searches the frequency ofHelicobacter pylori in these lesions in patients with chronic antral gastritis in Yaounde, Cameroon.Methods: Five gastric biopsies were performed during upper  gastrointestinal endoscopy for pathology and fixed in formol 10% before being coated in paraffin. Both the modified Giemsa and Periodic acid of Shift – Alkaline blue stains were used for the histological diagnosis of Helicobacter pylori infection. Hematoxylyn and eosin stain was used to determine the activity of gastritis, atrophic gastritis and intestinal  metaplasia in accordance to the Sydney’s classification of gastritis.Data were analysed using both the Epi info 6.04 and Excel 2007 softwares. Means and their standard deviations, medians and their interquartiles(IQR) were calculated. Proportions were established for qualitative variables and chi square analysis done in this study with a p value set at 0.05.Results: Seventy-nine patients with chronic antral gastritis were enrolled, of which 43 (54.4%) were male, median age: 43 years (range from 21 to 70 years). The rate of atrophic gastritis was 74.7% (59/79). The activity of atrophic gastritis was mild in 47.5% (28/59) of cases, moderate in 47.5% (28/59) and severe in 5% (5/59). Intestinal metaplasia and follicular  gastritis were present in 6.3% (5/79), and 10.1% (8/79), respectively.Concerning Helicobacter pylori infection, 71.2% (42/59) of patients with atrophic gastritis tested positive against 28.8% (17/59) who tested negative (p = 0.00003). Helicobacter pylori infection was related to the severity of gastric atrophy (p = 0.0001). Among patients with intestinalmetaplasia and follicular gastritis, the proportion of those who tested positive for Helicobacter pylori infection was 80% (4/5), and 75% (6/8),respectively. There were no significant differences in the occurrence of atrophic gastritis according to age groups (p = 0.908).Conclusion: This study concludes that atrophic gastritis, which is most often caused by Helicobacter pylori, is the most frequent precancerous condition of stomach in Cameroon. Routine gastric sampling for pathologic analysis is mandatory for effective diagnosis and surveillance of Helicobacter pylori infection and precancerous conditions of the stomach

Protective role of aqueous extract of Hibiscus sabdariffa (calyx) against potassium bromate induced tissue damage in wistar rats

The protective role of aqueous extract of Hibiscus sabdariffa (calyx) against potassium bromate induced tissue damage was investigated in rat tissues (brain, kidney, stomach, spleen, heart and liver). The rats were divided into four groups. Group A was administered with 0.25 M sucrose only (base line control), Group B with 60 mg/kg body weight of potassium bromate, and Group C with 250 mg/kg body weight of extracts. Group D was administered 500 mg/kg body weight of extract. Group A and B were used as control groups, while Group C and D were the experimentals. The oral administration of potassium bromate to groups B, C and D were done eight hours before sacrifice. Lipid peroxidation was monitored by colorimetric determination of amino acid, protein and malondialdehyde level in the tissues. The organ-to-body weight ratio was taken as indication for inflammation and necrosis of the tissues investigated. The results of the test groups were statistically (p < 0.05) compared with the base linecontrol and the group B. There was no significant difference in the organ-to-body weight ratio in all the tissues investigated at both doses, when compared with base line control, but showed a significant decrease when compared with group B. The protein level of the tissues investigated showed a similar trend but the stomach shows significant increase in the protein level. This may be due to accumulation of the toxicant inducing protein synthesis. Amino acid level decreased significantly when comparedwith the base-line control and group B. This may be due to the extract ability to reduce proteolysis. Malondialdehyde level in the test groups decreased significantly in a dose dependent manner in all tissues investigated

Measurement of the Spectral Shape of the beta-decay of 137Xe to the Ground State of 137Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden non-unique $\beta$-decay transition ^{137}\textrm{Xe}(7/2^-)\to\,^{137}\textrm{Cs}(7/2^+). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultra-low background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal-to-background ratio of more than 99-to-1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden non-unique $\beta$-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.Comment: Version as accepted by PR

Search for nucleon decays with EXO-200

A search for instability of nucleons bound in $^{136}$Xe nuclei is reported with 223 kg$\cdot$yr exposure of $^{136}$Xe in the EXO-200 experiment. Lifetime limits of 3.3$\times 10^{23}$ and 1.9$\times 10^{23}$ yrs are established for nucleon decay to $^{133}$Sb and $^{133}$Te, respectively. These are the most stringent to date, exceeding the prior decay limits by a factor of 9 and 7, respectively

Deep Neural Networks for Energy and Position Reconstruction in EXO-200

We apply deep neural networks (DNN) to data from the EXO-200 experiment. In the studied cases, the DNN is able to reconstruct the relevant parameters - total energy and position - directly from raw digitized waveforms, with minimal exceptions. For the first time, the developed algorithms are evaluated on real detector calibration data. The accuracy of reconstruction either reaches or exceeds what was achieved by the conventional approaches developed by EXO-200 over the course of the experiment. Most existing DNN approaches to event reconstruction and classification in particle physics are trained on Monte Carlo simulated events. Such algorithms are inherently limited by the accuracy of the simulation. We describe a unique approach that, in an experiment such as EXO-200, allows to successfully perform certain reconstruction and analysis tasks by training the network on waveforms from experimental data, either reducing or eliminating the reliance on the Monte Carlo.Comment: Accepted version. 33 pages, 28 figure