Respiratory Gas Exchange in the Resting Starry Flounder, Platichthys Stellatus: A Comparison with Other Teleosts

1979 ◽  
Vol 78 (1) ◽  
pp. 167-179
Author(s):  
CHRIS M. WOOD ◽  
B. R. McMAHON ◽  
D. G. McDONALD
Keyword(s):  
Cardiac Output ◽  
Rate Ratio ◽  
Peripheral Vascular ◽  
High Cardiac Output ◽  
Starry Flounder ◽  
Content Difference ◽  
Platichthys Stellatus ◽  
Wide Range ◽  
Ventilation Perfusion Ratio

A wide range of respiratory, ventilatory, and cardiovascular parameters have been recorded under completely resting conditions in the starry flounder (Platichthys stellatus), a generally inactive benthic teleost. The results differ in a number of important respects from those of a previous study on the same species. The present data have also been compared with those reported for the active pelagic rainbow trout (Salmo gairdnen) and for other teleost species. Of particular note in the flounder, relative to the trout, are low arterial and venous Poo2's, a low arterial-venous O2 content difference, a low transfer factor and high diffusion gradient for O2 across the gills, a high in vivo blood O2 affinity, a high cardiac output and stroke volume accompanied by a low peripheral vascular resistance, a low ventilation volume, a low ventilation-perfusion ratio, and a low capacity-rate ratio for O2 exchange at the gills. Parameters of CO2 transport and acidbase regulation appear conventional, though blood CO2 contents and lactate concentrations are low. The respiratory strategies of inactive versus active, and benthic versus pelagic teleosts are discussed. Note: Present address: Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.

Respiratory, Ventilatory, and Cardiovascular Responses to Experimental Anaemia in the Starry Flounder, Platichthys Stellatus

1979 ◽  
Vol 82 (1) ◽  
pp. 139-162
Author(s):  
CHRIS M. WOOD ◽  
B. R. McMAHON ◽  
D. G. MCDONALD
Keyword(s):  
Cardiac Output ◽  
Rainbow Trout ◽  
Exercise Performance ◽  
Cardiovascular Responses ◽  
O2 Uptake ◽  
Post Exercise ◽  
Starry Flounder ◽  
Platichthys Stellatus ◽  
Blood Ph ◽  
The Face

Unrestrained, quiescent starry flounder maintained approximately normal levels of O2 uptake in the face of severe experimental anaemia. At haematocrits above about 5 %, the only major compensation was a reduction in venous O2 tension which lowered venous saturation and thereby kept a constant difference between arterial and venous O2 contents. Below a haematocrit of about 5 %, this difference decreased, and many additional compensations were invoked, including increases in ventilation, expired O2 tension, arterial O2 tension, and cardiac output, and decreases in systemic vascular resistance and blood pH. All changes could be reversed by restoration of haematocrit. Exercise performance and post-exercise changes in blood pH and lactate differed only slightly between anaemic and normal flounder. In wild flounder, anaemia commonly occurs and apparently only causes death at the haematocrit value (about 5 %) below which most major compensations are implemented. The respiratory strategy of the flounder during anaemia is compared with that of the rainbow trout.

The respiratory responses of Carcinus maenas to declining oxygen tension

1976 ◽  
Vol 65 (2) ◽  
pp. 309-322 ◽  
Author(s):  
A. C. Taylor
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Tension ◽  
Rate Ratio ◽  
Carcinus Maenas ◽  
Level Of Activity ◽  
Wide Range ◽  
Oxygen Tensions ◽  
High Level ◽  
Respiratory Responses

The degree of respiratory independence shown by Carcinus under conditions of declining oxygen tension is dependent on the animal's level of activity. Inactive Carcinus are capable of maintaining respiratory independence down to a Po2 of 60–80 mmHg. This is achieved primarily by an increase in ventilation volume such that the amount of oxygen made available at the respiratory surfaces remains constant over a wide range of oxygen tension. The Po2 at which this can no longer be maintained corresponds closely to the Po2 at which respiratory independence is lost. Under normoxic conditions the Po2 of the post- and prebranchial blood was 97 and 18 mmHg respectively. At the high oxygen tensions prevailing in the postbranchial blood the respiratory pigment is fully saturated. Under conditions of declining oxygen tension the heart rate remains more or less constant until the Po2 reaches 60–80 mmHg, the onset of bradycardia coinciding with the loss of saturation of the haemocyanin. Although cardiac output falls during hypoxia, the capacity rate ratio remains approximately constant, which enables the effectiveness of oxygen uptake by the blood to remain at a high level.

Role of impaired myocardial relaxation in the production of elevated left ventricular filling pressure

2005 ◽  
Vol 288 (3) ◽  
pp. H1203-H1208 ◽  
Author(s):  
Ilan Hay ◽  
Jonathan Rich ◽  
Paul Ferber ◽  
Daniel Burkhoff ◽  
Mathew S. Maurer
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Myocardial Relaxation ◽  
End Diastolic Volume ◽  
Wide Range

Although present in many patients with heart failure and a normal ejection fraction, the role of isolated impairments in active myocardial relaxation in the genesis of elevated filling pressures is not well characterized. Because of difficulties in determining the effect of prolonged myocardial relaxation in vivo, we used a cardiovascular simulated computer model. The effect of myocardial relaxation, as assessed by τ (exponential time constant of relaxation), on pulmonary vein pressure (PVP) and left ventricular end-diastolic pressure (LVEDP) was investigated over a wide range of τ values (20–100 ms) and heart rate (60–140 beats/min) while keeping end-diastolic volume constant. Cardiac output was recorded over a wide range of τ and heart rate while keeping PVP constant. The effect of systolic intervals was investigated by changing time to end systole at the same heart rate. At a heart rate of 60 beats/min, increases in τ from a baseline to extreme value of 100 ms cause only a minor increase in PVP of 3 mmHg. In contrast, at 120 beats/min, the same increase in τ increases PVP by 23 mmHg. An increase in filling pressures at high heart rates was attributable to incomplete relaxation. The PVP-LVEDP gradient was not constant and increased with increasing τ and heart rate. Prolonged systolic intervals augmented the effects of τ on PVP. Impaired myocardial relaxation is an important determinant of PVP and cardiac output only during rapid heart rate and especially when combined with prolonged systolic intervals. These findings clarify the role of myocardial relaxation in the pathogenesis of elevated filling pressures characteristic of heart failure.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

Ethnomedicinal uses, Phytochemistry and Pharmacological Aspects of the Genus Berberis Linn: A Comprehensive Review

2020 ◽  
Vol 23 ◽  
Author(s):  
Roohi Mohi-ud-din ◽  
Reyaz Hassan Mir ◽  
Prince Ahad Mir ◽  
Saeema Farooq ◽  
Syed Naiem Raza ◽  
...  
Keyword(s):  
Chemical Constituents ◽  
Pharmacological Activities ◽  
Traditional Use ◽  
Comprehensive Review ◽  
Wide Range ◽  
Anti Cancer ◽  
Comprehensive Survey ◽  
Ethnomedicinal Uses

Background: Genus Berberis (family Berberidaceae), which contains about 650 species and 17 genera worldwide, has been used in folklore and various traditional medicine systems. Berberis Linn. is the most established group among genera with around 450-500 species across the world. This comprehensive review will not only help researchers for further evaluation but also provide substantial information for future exploitation of species to develop novel herbal formulations. Objective: The present review is focussed to summarize and collect the updated review of information of Genus Berberis species reported to date regarding their ethnomedicinal information, chemical constituents, traditional/folklore use, and reported pharmacological activities on more than 40 species of Berberis. Conclusion: A comprehensive survey of the literature reveals that various species of the genus possess various phytoconstituents mainly alkaloids, flavonoid based compounds isolated from different parts of a plant with a wide range of pharmacological activities. So far, many pharmacological activities like anti-cancer, anti-hyperlipidemic, hepatoprotective, immunomodulatory, anti-inflammatory both in vitro & in vivo and clinical study of different extracts/isolated compounds of different species of Berberis have been reported, proving their importance as a medicinal plant and claiming their traditional use.

Current Status and Future Perspective for Research on Medicinal Plants with Anticancerous Activity and Minimum Cytotoxic Value

2019 ◽  
Vol 20 (12) ◽  
pp. 1227-1243
Author(s):  
Hina Qamar ◽  
Sumbul Rehman ◽  
D.K. Chauhan
Keyword(s):  
Side Effects ◽  
Medicinal Plants ◽  
Anticancer Agents ◽  
Drug Targets ◽  
Psidium Guajava ◽  
Current Status ◽  
Future Perspective ◽  
Wide Range

Cancer is the second leading cause of morbidity and mortality worldwide. Although chemotherapy and radiotherapy enhance the survival rate of cancerous patients but they have several acute toxic effects. Therefore, there is a need to search for new anticancer agents having better efficacy and lesser side effects. In this regard, herbal treatment is found to be a safe method for treating and preventing cancer. Here, an attempt has been made to screen some less explored medicinal plants like Ammania baccifera, Asclepias curassavica, Azadarichta indica, Butea monosperma, Croton tiglium, Hedera nepalensis, Jatropha curcas, Momordica charantia, Moringa oleifera, Psidium guajava, etc. having potent anticancer activity with minimum cytotoxic value (IC50 >3μM) and lesser or negligible toxicity. They are rich in active phytochemicals with a wide range of drug targets. In this study, these medicinal plants were evaluated for dose-dependent cytotoxicological studies via in vitro MTT assay and in vivo tumor models along with some more plants which are reported to have IC50 value in the range of 0.019-0.528 mg/ml. The findings indicate that these plants inhibit tumor growth by their antiproliferative, pro-apoptotic, anti-metastatic and anti-angiogenic molecular targets. They are widely used because of their easy availability, affordable price and having no or sometimes minimal side effects. This review provides a baseline for the discovery of anticancer drugs from medicinal plants having minimum cytotoxic value with minimal side effects and establishment of their analogues for the welfare of mankind.

Approach in improving potency and selectivity of kinase inhibitors: Allosteric kinase inhibitors

2020 ◽  
Vol 21 ◽  
Author(s):  
Shangfei Wei ◽  
Tianming Zhao ◽  
Jie Wang ◽  
Xin Zhai
Keyword(s):  
Protein Interactions ◽  
Kinase Inhibitors ◽  
Binding Modes ◽  
Allosteric Inhibitors ◽  
Wide Range ◽  
Allosteric Sites ◽  
Protein Functions ◽  
Regulate Protein

: Allostery is an efficient and particular regulatory mechanism to regulate protein functions. Different from conserved orthosteric sites, allosteric sites have distinctive functional mechanism to form the complex regulatory network. In drug discovery, kinase inhibitors targeting the allosteric pockets have received extensive attention for the advantages of high selectivity and low toxicity. The approval of trametinib as the first allosteric inhibitor validated that allosteric inhibitors could be used as effective therapeutic drugs for treatment of diseases. To date, a wide range of allosteric inhibitors have been identified. In this perspective, we outline different binding modes and potential advantages of allosteric inhibitors. In the meantime, the research processes of typical and novel allosteric inhibitors are described briefly in terms of structureactivity relationships, ligand-protein interactions and in vitro and in vivo activity. Additionally, challenges as well as opportunities are presented.

In Silico Assessment of ADME Properties: Advances in Caco-2 Cell Monolayer Permeability Modeling

2019 ◽  
Vol 18 (26) ◽  
pp. 2209-2229 ◽  
Author(s):  
Hai Pham-The ◽  
Miguel Á. Cabrera-Pérez ◽  
Nguyen-Hai Nam ◽  
Juan A. Castillo-Garit ◽  
Bakhtiyor Rasulev ◽  
...  
Keyword(s):  
Intestinal Absorption ◽  
In Silico ◽  
Review Paper ◽  
Cell Monolayer ◽  
Cell Permeability ◽  
Drug Substances ◽  
Wide Range ◽  
Modeling Techniques

One of the main goals of in silico Caco-2 cell permeability models is to identify those drug substances with high intestinal absorption in human (HIA). For more than a decade, several in silico Caco-2 models have been made, applying a wide range of modeling techniques; nevertheless, their capacity for intestinal absorption extrapolation is still doubtful. There are three main problems related to the modest capacity of obtained models, including the existence of inter- and/or intra-laboratory variability of recollected data, the influence of the metabolism mechanism, and the inconsistent in vitro-in vivo correlation (IVIVC) of Caco-2 cell permeability. This review paper intends to sum up the recent advances and limitations of current modeling approaches, and revealed some possible solutions to improve the applicability of in silico Caco-2 permeability models for absorption property profiling, taking into account the above-mentioned issues.

Pleiotropic Effect of Mahanine and Girinimbine Analogs: Anticancer Mechanism and its Therapeutic Versatility

2019 ◽  
Vol 18 (14) ◽  
pp. 1983-1990 ◽  
Author(s):  
V. Lenin Maruthanila ◽  
Ramakrishnan Elancheran ◽  
Ajaikumar B. Kunnumakkar ◽  
Senthamaraikannan Kabilan ◽  
Jibon Kotoky
Keyword(s):  
Biological Effects ◽  
Pleiotropic Effect ◽  
In Vivo Evaluation ◽  
Chemopreventive Agents ◽  
Cycle Arrest ◽  
Wide Range ◽  
Anticancer Mechanism ◽  
Metastasis Development

Emerging evidence present credible support in favour of the potential role of mahanine and girinimbine. Non-toxic herbal carbazole alkaloids occur in the edible part of Murraya koenigii, Micromelum minutum, M. zeylanicum, and M. euchrestiolia. Mahanine and girinimbine are the major potent compounds from these species. In fact, they interfered with tumour expansion and metastasis development through down-regulation of apoptotic and antiapoptotic protein, also involved in the stimulation of cell cycle arrest. Consequently, these compounds were well proven for the in-vitro and in vivo evaluation that could be developed as novel agents either alone or as an adjuvant to conventional therapeutics. Therefore, mahanine and girinimbine analogs have the potential to be the promising chemopreventive agents for the tumour recurrence and the treatment of human malignancies. In this review, an updated wide-range of pleiotropic anticancer and biological effects induction by mahanine and girinimbine against cancer cells were deeply summarized.

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