617 research outputs found
Effect of temperature on the development, growth, survival and settlement of green mussel Perna viridis (Linnaeus, 1758)
The e¡ect of temperature on the development,
growth, survival and settlement of Perna viridis was
studied under controlled conditions to provide information
needed for the development of commercial
hatchery technology for green mussel P. viridis. Total
mortality of the larvae occurred after 24 h at temperatures
of 33 1C and 35 1C. At 24 1C, larvae took
longer to settle than at temperatures of 27 1C, 29 1C
and 31 1C. For optimum larval development (8^13 h),
growth (17.270.84 mmday^1) and survival (55.27
0.84%), a hatchery rearing temperature of 31 1C is
required. For settlement no signi¢cant di¡erence
was seen between the percentage settlement at
29 1C (49.373.34%) and 31 1C (45.871.76%). However,
the process of settlement began and ended earlier
at 29 1C (from15 to18 days) thanat 31 1C (from18
to 20 days). Thus for larval settlement a temperature
of 29 1C is recommended
Studies on induced maturation, spawning and larval settlement in green mussel Perna viridis (Linnaeus, 1758)
In the green mussel Perna viridis (Linnaeus, 1758), studies were undertaken on the
induced maturation, spawning, larval rearing and settlement.
Perna viridis broodstock could be conditioned or induced to mature out of the spawning
season by maintaining them at 23 ± 1 • C, at > 30 ppt salinity, pH 7.5 - 8.2 and fed with
Chaetoceros calcitrans at a cell concentration of lx 10 5 ml-1 fortified with 700 I.U. cod liver oil @
1 I animal-1day-1 in two installments for 15 and 32 days respectively.
All increase of 5 • C form the ambient water temperature at a salinity> 25 ppt and pH 7 -
8.2 with an addition of male or female gametes was able to induce 100 % spawning in 1 -2 hours
in P. viridis. No sex wise pattem was observed. None of the commonly used chemicals like
Hydrogen peroxide or Serotonin was able to elicit a full spawning response.
Studies on the effect of Physico - chemical parameters for larval rearing of P. viridis
showed that a temperature of 29 • C - 31 • C at high salinity > 30 ppt with 50 ppm
Chloramphenicol antibiotic at pH 8.2, with moderate aeration and fed with lsochrysis galbana, as
the best for optimum growth, percentage survival and settlement of spat.
Settlement preference indicated clearly that primary settling larvae required filamentous
substrates and among these byssus threads was the best substrate even though presence of
adult mussels significantly attracted more mussels.than byssal threads. High temperature 31• C,
moderate aeration, salinity of 25 - 38 ppt, pH 7 - 8 was optimum for larval settlement.
Among the various chemicals tried L-DOPA gave the best results with 100 % settlement
observed in 5 hours at 2.5 x 10 -7 M.
Remote setting was also successfully done with larvae transported in ambient moist
condition. A 24 hour transportation period did not significantly affect the percentage of P. viridis
larval survival or settlemen
Phagocytic activity in finfish Oreochromis mossambicus.
Aquaculture has grown into a significant industry in many parts of the world over the last twenty years. As fish farming is being done intensively under conditions o f high stocking density, infectious diseases pose a constant and costly threat to successful aquaculture. Even when environmental conditions are good and fishes are healthy, certain infectious agents, if introduced into the farm can cause heavy mortalities. Though
chemotherapy with chemicals and antibiotics have, to some extent helped to control a number o f bacterial, fungal and parasitic infections, there is still no cure for viral infections
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Can seafloor voltage cables be used to study large-scale circulation? An investigation in the Pacific Ocean
Marine electromagnetic (EM) signals largely depend on three factors: flow velocity, Earth's main magnetic field, and seawater's electrical conductivity (which depends on the local temperature and salinity). Because of this, there has been recent interest in using marine EM signals to monitor and study ocean circulation. Our study utilizes voltage data from retired seafloor telecommunication cables in the Pacific Ocean to examine whether such cables could be used to monitor circulation velocity or transport on large oceanic scales. We process the cable data to isolate the seasonal and monthly variations and then evaluate the correlation between the processed data and numerical predictions of the electric field induced by an estimate of ocean circulation. We find that the correlation between cable voltage data and numerical predictions strongly depends on both the strength and coherence of the model velocities flowing across the cable, the local EM environment, as well as the length of the cable. The cable within the Kuroshio Current had good correlation between data and predictions, whereas two of the cables in the Eastern Pacific Gyre – a region with both low flow speeds and interfering velocity directions across the cable – did not have any clear correlation between data and predictions. Meanwhile, a third cable also located in the Eastern Pacific Gyre showed good correlation between data and predictions – although the cable is very long and the speeds were low, it was located in a region of coherent flow velocity across the cable. While much improvement is needed before utilizing seafloor voltage cables to study and monitor oceanic circulation across wide regions, we believe that with additional work, the answer to the question of whether or not seafloor voltage cables can be used to study large-scale circulation may eventually be yes.
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Reticuloendothelial system of defense in Oreochromis mossambicus (Peters)
The reticuloendothelial system (RES) was studied in vivo in Oreochromis
mossambicus by injecting colloidal carbon particles. Histological and cytological
examination of the organs from 2 hours to day 10 after injection revealed
that the major organs of particle localization in O. mossambicus were spleen,
kidney, atrium of heart and dermis. Among these organs, spleen showed high
antigen trapping ability in its ellipsoids followed by kidney. In the heart the
ventricular endocardial cells were more phagocytic than the atrial endocardial
cells
Sputum Smear Microscopy at Two Months into Continuation-Phase: Should It Be Done in All Patients with Sputum Smear-Positive Tuberculosis?
BACKGROUND: The Revised National Tuberculosis Control Program (RNTCP) of India recommends follow-up sputum smear examination at two months into the continuation phase of treatment. The main intent of this (mid-CP) follow-up is to detect patients not responding to treatment around two-three months earlier than at the end of the treatment. However, the utility of mid-CP follow-up under programmatic conditions has been questioned. We undertook a multi-district study to determine if mid-CP follow-up is able to detect cases of treatment failures early among all types of patients with sputum smear-positive TB. METHODOLOGY: We reviewed existing records of patients with sputum smear-positive TB registered under the RNTCP in 43 districts across three states of India during a three month period in 2009. We estimated proportions of patients that could be detected as a case of treatment failure early, and assessed the impact of various policy options on laboratory workload and number needed to test to detect one case of treatment failure early. RESULTS: Of 10055 cases, mid-CP follow-up was done in 6944 (69%) cases. Mid-CP follow-up could benefit 117/8015 (1.5%) new and 206/2040 (10%) previously-treated sputum smear-positive cases by detecting their treatment failure early. Under the current policy, 31 patients had to be tested to detect one case of treatment failure early. All cases of treatment failure would still be detected early if mid-CP follow-up were discontinued for new sputum smear-positive cases who become sputum smear-negative after the intensive-phase of treatment. This would reduce the related laboratory workload by 69% and only 10 patients would need to be tested to detect one case of treatment failure early. CONCLUSION: Discontinuation of mid-CP follow-up among new sputum smear-positive cases who become sputum smear-negative after completing the intensive-phase of treatment will reduce the laboratory workload without impacting overall early detection of cases of treatment failure
Administration of ON 01210.Na after exposure to ionizing radiation protects bone marrow cells by attenuating DNA damage response
<p>Abstract</p> <p>Background</p> <p>Ionizing radiation-induced hematopoietic injury could occur either due to accidental exposure or due to diagnostic and therapeutic interventions. Currently there is no approved drug to mitigate radiation toxicity in hematopoietic cells. This study investigates the potential of ON 01210.Na, a chlorobenzylsulfone derivative, in ameliorating radiation-induced hematopoietic toxicity when administered after exposure to radiation. We also investigate the molecular mechanisms underlying this activity.</p> <p>Methods</p> <p>Male C3H/HeN mice (n = 5 mice per group; 6-8 weeks old) were exposed to a sub-lethal dose (5 Gy) of γ radiation using a <sup>137</sup>Cs source at a dose rate of 0.77 Gy/min. Two doses of ON 01210.Na (500 mg/kg body weight) were administered subcutaneously at 24 h and 36 h after radiation exposure. Mitigation of hematopoietic toxicity by ON 01210.Na was investigated by peripheral white blood cell (WBC) and platelet counts at 3, 7, 21, and 28 d after radiation exposure. Granulocyte macrophage colony forming unit (GM-CFU) assay was done using isolated bone marrow cells, and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) was performed on bone marrow sections at 7 d post-exposure. The DNA damage response pathway involving ataxia telangiectasia mutated (ATM) and p53 was investigated by Western blot in bone marrow cells at 7 d post-exposure.</p> <p>Results</p> <p>Compared to the vehicle, ON 01210.Na treated mice showed accelerated recovery of peripheral WBC and platelet counts. Post-irradiation treatment of mice with ON 01210.Na also resulted in higher GM-CFU counts. The mitigation effects were accompanied by attenuation of ATM-p53-dependent DNA damage response in the bone marrow cells of ON 01210.Na treated mice. Both phospho-ATM and phospho-p53 were significantly lower in the bone marrow cells of ON 01210.Na treated than in vehicle treated mice. Furthermore, the Bcl2:Bax ratio was higher in the drug treated mice than the vehicle treated groups.</p> <p>Conclusions</p> <p>ON 01210.Na treatment significantly mitigated the hematopoietic toxicity induced by a sub-lethal radiation dose. Mechanistically, attenuation of ATM-p53 mediated DNA damage response by ON 01210.Na is contributing to the mitigation of radiation-induced hematopoietic toxicity.</p
Quantifying the Impact of Immune History and Variant on SARS-CoV-2 Viral Kinetics and Infection Rebound: A Retrospective Cohort Study
BACKGROUND: The combined impact of immunity and SARS-CoV-2 variants on viral kinetics during infections has been unclear.
METHODS: We characterized 1,280 infections from the National Basketball Association occupational health cohort identified between June 2020 and January 2022 using serial RT-qPCR testing. Logistic regression and semi-mechanistic viral RNA kinetics models were used to quantify the effect of age, variant, symptom status, infection history, vaccination status and antibody titer to the founder SARS-CoV-2 strain on the duration of potential infectiousness and overall viral kinetics. The frequency of viral rebounds was quantified under multiple cycle threshold (Ct) value-based definitions.
RESULTS: Among individuals detected partway through their infection, 51.0% (95% credible interval [CrI]: 48.3-53.6%) remained potentially infectious (Ct
CONCLUSIONS: SARS-CoV-2 viral kinetics are partly determined by immunity and variant but dominated by individual-level variation. Since booster vaccination protects against infection, longer clearance times for BA.1-infected, boosted individuals may reflect a less effective immune response, more common in older individuals, that increases infection risk and reduces viral RNA clearance rate. The shifting landscape of viral kinetics underscores the need for continued monitoring to optimize isolation policies and to contextualize the health impacts of therapeutics and vaccines.
FUNDING: Supported in part by CDC contract #200-2016-91779, a sponsored research agreement to Yale University from the National Basketball Association contract #21-003529, and the National Basketball Players Association
Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial
Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy.
Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388.
Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001).
Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice
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