RESUMEN
This study was conducted to observe the stock assessments of Tengara (Mystus tengara) in three different management systems of Baors (Oxbow lake) such as System-1, System-2, and System-3. In this study, 1806 specimens were sampled using traditional fishing nets to observe growth pattern, population structure, growth parameters, natural mortality (M), fishing mortality (F), total mortality (Z), recruitment pattern, exploitation rate (E), relative yield per-recruit (Y'/R), optimum catchable length, length at first capture, steady state biomass (SSB), and maximum sustainable yield (MSY) from January to December 2021. Digital slide calipers and a digital balance were used to measure each individual's total length (TL) and body weight (BW), respectively. An empirical maximum length-based model was used to calculate size at first sexual maturity (Lm), and optimum catchable length (Lopt) was calculated based on asymptotic length (L∞). The least square linear regression equation was used to determine the regression parameters. The value of regression parameter, 'b' was 3.01 for system-1, 2.78 for system-2, and 2.70 for system-3, indicating that growth pattern of Tengara is isometric in system-1, but negative allometric growth in system-2 and system-3. The highest asymptotic length (L∞) and weight (W∞) of Tengara were found in system-1 (11.19 cm and 13.67 g) in comparison with system-2, (10.98 cm and 12.49 g) and system-3 (9.09 cm and 6.96 g) respectively. The growth coefficient (K) of the von Bertalanffy growth function (VBGF) was 0.72 year-1, 0.72 year-1, and 0.73 year-1 for system-1, system-2 and system-3, respectively. The calculated M, F, Z were 1.72, 1.28, and 3.00 year-1 for system-1, 1.11, 0.67 and 1.78 year-1 for system-2 and 1.12, 0.84 and 1.96 year-1 for system-3 respectively. The calculated life span (tmax) was found 4.19 years for system-1, 4.15 years for system-2 and 4.12 years for system-3. The recruitment patterns showed that the highest relative percentage of recruits were found in July, June and September for system-1, system-2 and system-3 respectively, with the major recruitment peak occurring from April to June for system-1, May to June for system-2 and June to July for system-3. One minor recruitment peak also occurred from August to September in system-1. The exploitation rate was more or less same in all three systems indicating that Tengara is under exploited from all the Baors. The significantly highest SSB and MSY were found in system-1 (22.65 and 12.11 metric tons), compared to system-2 (16.16 and 10.28 metric tons) and system-3 (5.55 and 5.49 metric tons), respectively. Considering the values of regression parameters, recruitment pattern, SSB and MSY, system-1 was found more suitable for Tengara compared to system-2 and system-3 management practices of Baors. Finally, these findings will turn out to be paradigm for the impregnable management of Tengara in Baors of southwest Bangladesh.
RESUMEN
BACKGROUND: Gastric cancer is also a leading cancer in Bangladesh like that of the global incidences. It is speculated that environmental, bacterial infection and molecular factors might have been carrying the key role of rising trend of the disease. This study was aimed to investigate the association of mutated p53 gene with of Helicobacter pylori (H. pylori) infection, clinicopathological and some environmental factors of the gastric cancer patients. METHODS: This cross-sectional study was carried out from January 2015 to December 2016 in a specialized cancer hospital of Bangladesh. Patients were selected randomly who were admitted for surgical intervention after diagnosis as adenocarcinoma of the stomach and physically fit for surgery. After admission proper evaluation of the patients was done. Tissue sample from the gastrectomy specimen along with the blood sample was sent to the related laboratories. After DNA extraction for p53, exons 5 and 6, they were adjusted for proper primer designing. Appropriate sequencing analysis of the result was done. Status of p53 was investigated to see their association with the result of the H. pylori, age and sex, tumor status, smoking and extra salt intake of the patients. Result of the study was calculated and analyzed by Chi-square and binomial logistic regression to find the association amongst them. RESULTS: Among the 71 patients, mean age was 52.96 years old, male: female ratio were 48:23, age group above 41 years were 53 (74.6%), proliferative and ulceroproliferative group of the tumor dominated (87.3%). There were 52 cases with (73.2%) p53 mutation. Among the 51 H. pylori positive cases, 41 (80%) had p53 mutation (P = 0.033). Tumor size and lymph node status were found to be associated with the gene mutation (P = 0.05). Age also had strong correlation with the mutation (P = 0.015). Gene mutation was found mostly among the younger (≤ 40 years) group of patients (94.4%). Patient with extra salt intake was also found related with the mutation (P = 0.03). CONCLUSIONS: Environmental and genetic factors seem to be risk factors for gastric cancer in Bangladesh. Nationwide anti H. pylori drive and further molecular research could elicit the other risk factors which might help to reduce the gastric cancer incidences in the country after taking appropriate measures.