Nitroglycerin induces late preconditioning against myocardial stunning via a PKC-dependent pathway

1999 ◽  
Vol 277 (6) ◽  
pp. H2488-H2494 ◽  
Author(s):  
Supratim Banerjee ◽  
Xian-Liang Tang ◽  
Yumin Qiu ◽  
Hitoshi Takano ◽  
Srinivas Manchikalapudi ◽  
...  
Keyword(s):  
Myocardial Stunning ◽  
Late Phase ◽  
Group Iv ◽  
Control Group ◽  
Wall Thickening ◽  
Signaling Mechanism ◽  
No Donors ◽  
Group Iii ◽  
Late Preconditioning ◽  
Group I

Previous studies have shown that administration of nitric oxide (NO) donors induces a delayed cardioprotective effect indistinguishable from the late phase of ischemic preconditioning (PC). However, the ability of clinically relevant NO donors to elicit this phenomenon has not been evaluated. In this study we tested whether an NO-releasing agent that is nitroglycerin (NTG), which is widely used clinically, can mimic the late phase of ischemic PC. Four groups of conscious rabbits underwent six cycles of 4-min occlusion (O)/4-min reperfusion (R) for 3 consecutive days ( days 1, 2, and 3). The severity of myocardial stunning was assessed as the total deficit of systolic wall thickening (WTh) after the last O/R cycle. In the control group ( group I, n = 6), the total deficit of WTh was reduced by 50% and 51% on days 2 and 3 vs. day 1, respectively, indicating late PC against stunning. Pretreatment with NTG (2 μg ⋅ kg−1 ⋅ min−1iv over 1 h) on day 0 ( group II, n = 6) was as effective as ischemic PC in mitigating myocardial stunning 24 h later ( day 1); on days 2 and 3, no further reduction of stunning was seen. Coadministration of the PKC inhibitor chelerythrine (5 mg/kg) with NTG ( group III, n = 6) completely abrogated the NTG-induced protection. Pretreatment with chelerythrine alone ( group IV, n = 5) did not alter stunning. These results demonstrate that a relatively brief infusion of NTG induces a robust protective effect against stunning 24 h later via a protein kinase C (PKC)-dependent signaling mechanism. The magnitude of NTG-induced protection is equivalent to that observed during the late phase of ischemic PC. Late PC induced by brief treatment with NTG could be a useful therapeutic strategy for myocardial protection in patients with ischemic heart disease.

Increased protein synthesis is necessary for the development of late preconditioning against myocardial stunning

1999 ◽  
Vol 277 (3) ◽  
pp. H874-H884 ◽  
Author(s):  
Ali Rizvi ◽  
Xian-Liang Tang ◽  
Yumin Qiu ◽  
Yu-Ting Xuan ◽  
Hitoshi Takano ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Myocardial Stunning ◽  
Late Phase ◽  
Group Vi ◽  
Group V ◽  
Group Iii ◽  
Late Preconditioning ◽  
Protein Pool ◽  
Group I ◽  
Delayed Toxicity

In phase I of this study, the rate of protein synthesis was measured by the incorporation of [3H]leucine into the protein pool in the heart of conscious rabbits. At 2 h after ischemic preconditioning (PC) with six 4-min occlusion/4-min reperfusion (O/R) cycles ( group II), the [3H]leucine content in the ischemic-reperfused region was increased by 82% compared with that in controls ( group I), indicating increased protein synthesis. This increase was completely abrogated by pretreatment with cycloheximide (CH; group III). In phase II, rabbits underwent six O/R cycles for three consecutive days ( days 1–3). Controls ( group IV) exhibited late PC against myocardial stunning on days 2 and 3. In group V, which received CH 30 min before the 1st O/R cycle on day 1 (same dose as group III), late PC against stunning on day 2 was completely abrogated. In group VI, pretreatment with CH 24 h before the 1st sequence of O/R cycles had no effect on myocardial stunning on day 1, indicating that the absence of late PC on day 2 in group V cannot be ascribed to delayed toxicity of CH. Taken together, these results demonstrate that, in the conscious rabbit, ischemic PC causes a rapid increase in myocardial protein synthesis and that this increased protein synthesis (or at least a fraction of it) is necessary for the development of the protection against myocardial stunning 24 h later. The late phase of ischemic PC is therefore dependent on the formation of new proteins in intact animals.

Analysis of surface conditioning methods on core-veneer bond strength of CAD/CAM zirconia restorations

2020 ◽  
pp. 1-11
Author(s):  
Anip K. Roy ◽  
Govind N. Prasad ◽  
Tushar V. Bhagat ◽  
Saurabh Chaturvedi ◽  
Vishwanath Gurumurthy ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Group Iv ◽  
Control Group ◽  
Group Iii ◽  
Surface Conditioning ◽  
Group I ◽  
Alumina Particles ◽  
Scanning Electron

BACKGROUND: The increased strength of zirconia has resulted in its widespread application in clinical dentistry. Nevertheless, the fracture of veneering porcelains remains one of the key reasons of failure. OBJECTIVE: The objective of this study was to compare and analyze the influence of surface conditioning methods on the core-veneer bond strength of zirconia restorations. METHODS: Thirty specimens of zirconia core with sizes 10 × 5 × 5 mm were layered with porcelain of sizes 5 × 3 × 3 mm. On the basis of different surface conditioning methods, four groups were made: Group I: abrasion with airborne alumina particles of 110 μm size, Group II: sandblasting with silica coated alumina particles of 50 μm in size, Group III (modified group): alteration with a coating of zirconia powder prior to sintering, and Group IV (control group): metal core specimens. The shear force of all specimens was tested using a universal testing machine with a 0.5 mm/min crosshead speed. One-way analysis of variance (ANOVA) and Tukey’s post hoc pair wise comparison (p= 0.05) were performed to analyze the shear bond strength. A scanning electron microscope was used to assess the fractured specimens. RESULTS: A statistically significant difference was noted between the groups. The mean value of shear bond strength was 40.25 MPa for Group I, 41.93 MPa for Group II, 48.08 MPa for Group III and 47.01 MPa for Group IV. CONCLUSIONS: The modified zirconia group and control group demonstrated a significantly higher mean bond strength than that of Group I, where airborne particle abrasion was used. The scanning electron microscope showed that cohesive fracture in the porcelain veneers was the main problem of failure in altered zirconia. The modified zirconia specimens in Group III demonstrated significantly improved values of shear bond strength.

Protein tyrosine kinase signaling is necessary for NO donor-induced late preconditioning against myocardial stunning

2003 ◽  
Vol 284 (4) ◽  
pp. H1441-H1448 ◽  
Author(s):  
Xian-Liang Tang ◽  
Eitaro Kodani ◽  
Hitoshi Takano ◽  
Michael Hill ◽  
Ken Shinmura ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Myocardial Stunning ◽  
Protein Tyrosine Kinase ◽  
Late Phase ◽  
Recovery Period ◽  
Wall Thickening ◽  
No Donor ◽  
Signaling Mechanism ◽  
Protein Tyrosine ◽  
Conscious Rabbits

Although protein tyrosine kinases (PTKs) signaling has been implicated in the late phase of ischemic preconditioning (PC), it is unknown whether PTK signaling is necessary for the development of nitric oxide (NO) donor-induced late PC. Thus conscious rabbits underwent a sequence of six 4-min coronary occlusion (O)/4-min reperfusion (R) cycles followed by a 5-h recovery period of reperfusion for 3 consecutive days ( days 1, 2, and 3). On day 0 (24 h before the 6 O/R cycles on day 1), rabbits received no treatment (control), the NO donor diethylenetriamine (DETA)/NO (DETA/NO), the PTK inhibitor 4-amino-5-(4-chlorophenyl)-7-( t-butyl)pyrazolo[3,4- d]pyrimidine (PP2), or DETA/NO plus PP2 (DETA/NO + PP2). In control rabbits ( n = 6), the six O/R cycles on day 1resulted in delayed functional recovery, indicating severe myocardial stunning. In rabbits pretreated with DETA/NO ( n = 5) on day 1, myocardial stunning caused by the six O/R cycles on day 1 was markedly attenuated, with a significant reduction (∼60%) in the total deficit of wall thickening (WTh) compared with controls, indicating that DETA/NO induced a late PC effect against stunning. However, in rabbits pretreated with DETA/NO + PP2 ( n = 5), the total deficit of WTh was significantly greater than that in rabbits treated with DETA/NO alone and was similar to that in controls, indicating that PP2 prevented the development of DETA/NO-induced late PC. In rabbits pretreated with PP2 on day 0 ( n = 4), the total deficit of WTh was similar to that in controls, indicating that PP2 does not affect myocardial stunning in itself. We conclude that a PTK-dependent signaling mechanism is necessary for the development of NO donor-induced late PC against myocardial stunning in conscious rabbits.

A Study on the Effect of Samoa Extract (Cleome droserifolia) on Sperm Quality in Male Albino Rats Exposed to Pyrethroid

2021 ◽  
pp. 39-45
Author(s):  
Nura I. Al-Zail ◽  
Salah F. Kamies
Keyword(s):  
Sperm Quality ◽  
Group Iv ◽  
Male Rats ◽  
Control Group ◽  
Albino Rats ◽  
Protective Agent ◽  
Group V ◽  
Group Iii ◽  
Group I ◽  
Induced Changes

Pyrethroid cyhalothrin (PC) is an insecticide that is used worldwide for pest control in agriculture and household use. Samoa extract (SE) is a potent antioxidant protecting cells from oxidative stress. The present study investigates the protective and therapeutic effect of SE on PC-induced changes in sperm quality in male rats. Fifty adult male albino rats were divided into five groups: group I: served as control; group II: received PC i.p. only (6.2 mg/kg b.wt.); group III: received SE only (100 mg/kg b.wt., p.o.) for eight weeks; group IV: received SE as a protective agent daily for eight weeks, then followed by the administration of PC (i.p.) three times a week for two weeks; group V: exposed to PC (i.p.) three times a week for two weeks, then treated with the SE daily for 8 weeks. Results showed that PC caused markedly impaired sperm quality (a count, viability, motility, and abnormality). Compared to PC-treated animals, SE in the protective group markedly restored the alteration of sperm indices. However, SE in the curative group was found to be less effective in restoring PC-induced alterations. In conclusion, the data of this study revealed that the SE as a protective agent is more effective than as a therapeutic agent. Keywords: Samoa; Pyrethroid; Sperm quality; Rat

Adaptive dose response pilot study of intravaginal Prostaglandin E2 application in free farrowing sows during parturition

2020 ◽  
Author(s):  
Ramona Bill ◽  
Heiko Nathues ◽  
Alexander Grahofer
Keyword(s):  
Prostaglandin E2 ◽  
Total Duration ◽  
Group Iv ◽  
Control Group ◽  
Birth Process ◽  
Group Iii ◽  
Beneficial Effects ◽  
Group I ◽  
Group Ii ◽  
Meconium Staining

Abstract Background The duration of birth is an important factor influencing the survival of piglets and the health of sows. A prolonged parturition is usually treated with oxytocin, even though several undesirable side effects are described. Therefore, the aim of this study was to evaluate the safety and efficacy of Prostaglandin E2 (PGE2) of different concentrations as an intravaginal applied gel in sows. MethodsTwelve sows were randomly allocated to one of four treatment groups: Group I (control group) application of placebo gel; Group II application of 2.0 mg PGE2; Group III application of 1.0 mg PGE2; Group IV application of 0.5 mg PGE2. The gel was administered intravaginal after the birth of the fourth piglet. Total duration of birth (time between first piglet and last placenta), piglet interval and placenta expulsion duration (time between first and last placenta) were recorded, and each piglet was scored for meconium staining and vitality. Furthermore, stillborn piglets were categorized into ante-partum and intra-partum deaths. Results Although no significant differences between the groups were detected, a beneficial tendency in several parameters was observed in group III. The duration of birth was 284 min (average of 14.3 piglets per litter), whereas in all other groups it was more than 400 min (average of 18.0 piglets per litter). The piglet interval was 10.1 min in group II compared to 10.2 min in group III, 16 min in group IV and 21.4 min in group I. In group III the placenta expulsion duration was 119 min in contrast to the other groups with more than 266 min. Severe meconium staining in more than 10% of piglets was observed in group II and IV. Moreover, piglets of group II showed oedematous and haemorrhagic umbilical cords, lethargy and anoxia, and intra-partum deaths were recorded. Conclusion Although the sample size is limited in this study, it is assumed that an application of 1mg PGE2 intra-partum instead of lower or higher dosages has the most beneficial effects on the birth process in sows and on the vitality of piglets. Further investigation is necessary to confirm the positive effect of PGE2 in daily practise.

scholarly journals ESTUDO COMPARATIVO ENTRE O FIO DE NAILON E A LINHA DE PESCA (POLIAMIDA) E A SUA APLICABILIDADE COMO FIO CIRÚRGICO

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
SHEILA CANEVESE RAHAL ◽  
MANOEL ÁLVARO GUIMARÃES ◽  
JOSÉ VICENTE FORTES ◽  
HÉLIO LANGONI ◽  
PEDRO HELIO LUCCHIARI
Keyword(s):  
Adverse Effect ◽  
Comparative Study ◽  
Physical Properties ◽  
Group Iv ◽  
Experimental Results ◽  
Control Group ◽  
Group Iii ◽  
Nylon Thread ◽  
Group I ◽  
Mucous Membranes

"Linhas de pesca"* em diâmetros de 0,15mm; 0,20mm; 0,25mm; 0,30mm foram divididas em quatro grupos, contendo dez amostras de cada diâmetro: grupo I - controle; grupo II - linhas colocadas em frasco com pastilhas de formalina; grupo III - um ciclo de autoclavagem (30 minutos à 121 C, seguido por 10 minutos de secagem à 37 C em estufa); grupo IV - dois ciclos de autoclavagens. Foram avaliadas quanto: comprimento, calibre, resistência no nó e alongamento. Comparativamente foram examinados fios de náilon cirúrgico nas numerações 0, 1-0, 2-0, 3-0, 4-0 e 5-0 (10 amostras de cada um). Pelos resultados da análise estastística, verificou-se que a esterilização pelo calor úmido exerceu um efeito adverso na resistência da "linha de pesca". Por outro lado não houve diferenças na resistência, calibre e alongamento da "linha de pesca" entre o primeiro e segundo ciclo de autoclavagem. As “linhas” mantidas em pastilhas de formalina mantiveram na sua maioria suas características originais de resistência, comprimento, diâmetro e alongamento quando comparada ao grupo controle, entretanto, cabe lembrar que o formaldeído é considerado irritante para pele e membrana mucosa. Foi possível concluir que a "linha de pesca" apresenta características semelhantes ao fio cirúrgico, podendo ser mantida em pastilhas de formalina ou esterilizada em autoclave, lembrando que a autoclavagem altera algumas de suas propriedades físicas. Abstract A comparative study has been carried out between fishing lines and nylon thread in regard to their applicability as surgical thread. Four groups of 10 fishing lines in each of the following diameters = 0.15, 0.20, 0.25 and 0.30 mm = were subjected to the following treatments: group I, control; group II sterilized with formalin tablets; group III, autoclaved 30 minutes at 121oC; group IV, autoclaved twice 30 minutes at 121oC. The following parameters were then considered: length, caliber, resistance at the knot, and elongation. Ten samples of each surgical 0, 1.0, 2.0, 3.0, 4.0 and 5.0 nylon threads were used in comparatively similar experiments as the ones carried out with the fishing lines. According to the statistical analyses of the experimental results, it has been found that the sterilization by means of the humid heat exerts an adverse effect on the resistance of the fishing line. However, no differences were found between the effect displayed by two cycles sterilization compared with the fishing lines subjected to only one cycle. The threads maintained in formalin kept the majority of their original properties of resistance, length, diameter and elongation when compared with the control group. It is known, however that formaldehyde is an irritant chemical towards the skin and the mucous membranes. It was possible to conclude: a. fishing lines display characteristics similar to that ones of the nylon surgical thread; b. they can be maintained in formalin solution; c. autoclave sterilization alters some of their physical properties.

Protective effect of L-carnitine against oxidative damage caused by experimental chronic aflatoxicosis in quail (Coturnix coturnix)

2005 ◽  
Vol 53 (3) ◽  
pp. 319-324 ◽  
Author(s):  
M. Citil ◽  
V. Gunes ◽  
O. Atakisi ◽  
Ayla Ozcan ◽  
M. Tuzcu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Whole Blood ◽  
Reduced Glutathione ◽  
Group Iv ◽  
Control Group ◽  
Total Aflatoxin ◽  
Group Iii ◽  
Coturnix Coturnix ◽  
Group I ◽  
Plasma Malondialdehyde

This study was designed to evaluate the effect of L-carnitine supplementation on the plasma malondialdehyde (MDA) and whole blood reduced glutathione (GSH) concentrations in experimentally-induced chronic aflatoxicosis in quails. For this purpose, a total of 80 quails up to 8 weeks old were divided into four equal groups. Group I served as control, Group II was given L-carnitine at the dose of 200 mg/litre in the drinking water for 60 days, Group III was given 60 µg total aflatoxin/kg diet for 60 days, and Group IV was given both 60 µg total aflatoxin/kg diet and 200 mg L-carnitine/litre in the drinking water for 60 days. Aflatoxin treatment caused a significant increase in plasma MDA and a significant decrease in blood GSH concentrations. On the other hand, there was a significant decrease in plasma MDA and a significant increase in whole blood GSH in the L-carnitine-supplemented group. The present study demonstrated that L-carnitine brought about the inhibition of lipid peroxidation by enhancing antioxidant capacity in quails with chronic aflatoxicosis.

scholarly journals Comparative Evaluation of Apical Sealing Ability of Different Obturation Techniques by Confocal Microscopy: An In Vitro Study

2020 ◽  
Vol 8 (02) ◽  
pp. 55-59
Author(s):  
Reetu Arora ◽  
Yogesh Kumar ◽  
Neetu Jindal ◽  
Renu Aggarwal ◽  
Kavneet Takhar
Keyword(s):  
Root Canal ◽  
Negative Control Group ◽  
Positive Control ◽  
Negative Control ◽  
Group Iv ◽  
Control Group ◽  
Group Vi ◽  
Group V ◽  
Group Iii ◽  
Group I

Abstract Introduction The aim of obturation in the root canal is to completely seal the canal space to eliminate all the portals of entry and exit between root canal and periodontal space. Various techniques have been developed to achieve a hermetic seal. Materials and Methods As many as 150 extracted human maxillary central incisors were taken for the study. Biomechanical preparation was done up to F5 protaper file. According to different obturation techniques, samples were divided into six groups, keeping 30 samples in experimental and 15 samples in control groups. Group I–Lateral Condensation, Group II–Thermafil, Group III–Beefill, Group IV–GuttaFlow, Group V–Positive Control group, Group VI–Negative Control group. After obturation, the samples were immersed in 2% Rhodamine-B dye for 24 hours. Each sample was longitudinally sectioned to examine under confocal laser scanning microscope. Statistical Analysis The results were evaluated with ANOVA and posthoc Tukey honest significant difference (HSD) comparison test. Results The mean values of dye penetration of different groups were Group I (Lateral Condensation) 1.51 ± 0.451, Group II (Thermafil) 0.918 ± 0.399, Group III (Beefill) 1.30 ± 0.559. Group IV (GuttaFlow) 0.655 ± 0.396, Group V (Positive Control group) 1.96 ±0.046, Group VI (Negative Control group) 0 ± 0. The lowest mean value of apical microleakage was found in GuttaFlow amongst all experimental groups. Conclusion It can be concluded that the GuttaFlow obturating material exhibited better apical sealing ability with canal walls.

Oxidant species trigger late preconditioning against myocardial stunning in conscious rabbits

2002 ◽  
Vol 282 (1) ◽  
pp. H281-H291 ◽  
Author(s):  
Xian-Liang Tang ◽  
Hitoshi Takano ◽  
Ali Rizvi ◽  
Julio F. Turrens ◽  
Yumin Qiu ◽  
...  
Keyword(s):  
Myocardial Stunning ◽  
Cumene Hydroperoxide ◽  
High Plasma ◽  
Vehicle Group ◽  
Wall Thickening ◽  
Oxygen Species ◽  
Group Vi ◽  
Late Preconditioning ◽  
Group I ◽  
Conscious Rabbits

Conscious rabbits underwent six 4-min occlusion and 4-min reperfusion cycles for 3 consecutive days ( day 1, 2, and 3); on day 1, rabbits received intravenous vehicle [preconditioning (PC)] ( group I, n = 6), superoxide dismutase (SOD; group II, n = 5), catalase ( group III, n = 6), or the hydroxyl radical (· OH) and peroxynitrite (ONOO−) scavenger N-2-mercaptopropionyl glycine (MPG [group IV], n = 6). In the PC group, the recovery of systolic wall thickening (WTh) after the sixth reperfusion was markedly improved on days 2 and 3 compared with day 1 and the total deficit of WTh was correspondingly reduced, indicating a late PC effect against myocardial stunning. Neither SOD nor catalase had any significant effect on the severity of stunning on day 1 or on the development of late PC on days 2 and 3, despite high plasma levels. In contrast, MPG markedly attenuated the severity of stunning on day 1 and prevented the development of late PC on day 2. Two additional groups of rabbits received an intracoronary infusion of vehicle ( group V, n = 4) or the reactive oxygen species (ROS) generating solution [cumene hydroperoxide (CuOOH, group VI, n = 7)] on day 0, and were then subjected to the six occlusion/reperfusion cycles on days 1, 2, and 3. In group VI, infusion of CuOOH elicited a late PC effect 24 h later (on day 1). Taken together, these results demonstrate that oxidant species play an essential role in triggering the development of late PC against stunning in conscious rabbits. The fact that late PC was blocked by MPG and mimicked by CuOOH implicate ONOO− and/or ·OH as the oxygen species responsible for the initiation of this phenomenon. In addition, the finding that exogenous ROS (CuOOH) reproduced the phenotype of late PC indicates that ROS are not only necessary but also sufficient to trigger this defensive adaptation of the heart to stress.

scholarly journals Remifentanil and Propofol Sedation for Retrobulbar Nerve Block

2002 ◽  
Vol 30 (4) ◽  
pp. 433-437 ◽  
Author(s):  
V. Rewari ◽  
R. Madan ◽  
H. L. Kaul ◽  
L. Kumar
Keyword(s):  
Adverse Effects ◽  
Respiratory Depression ◽  
Study Groups ◽  
Group Iv ◽  
Control Group ◽  
Group Iii ◽  
Group I ◽  
Retrobulbar Block ◽  
Significant Movement ◽  
Group Ii

We studied remifentanil and propofol for analgesia and sedation during the placement of an ophthalmic block. Eighty ASA I or II patients undergoing elective cataract surgery under a retrobulbar block in a rural camp setting were included in the study. Patients were randomly divided into four groups and received different drug combinations as follows: Group I—remifentanil 1 μg/kg, Group II—remifentanil 0.5 μg/kg and propofol 0.5 mg/kg, Group III— remifentanil 1 μg/kg with propofol 0.5 mg/kg and Group IV—saline 0.1 ml/kg. Patients were observed for degree of movement, sedation, pain, recall and respiratory depression. No patient in the study groups reported pain or displayed movement whereas most of the patients in the control group had significant pain during the placement of the block. Also, seven (35%) patients in the control group showed significant movement which may have led to failure of block in two patients and retrobulbar haemorrhage in one patient. Incidence of significant respiratory depression was maximum in Group III patients (60%), followed by Group I (20%) and least in Group II (5%). All patients in the study groups remained cooperative and obeyed commands except four patients in group III (OAA/S-4). Postoperatively, other than the control group, recall was maximum in Group I (55%) and least in Group II (5%). Hence, a combination of remifentanil 0.5 μg/kg with propofol 0.5 mg/kg as a bolus was considered to provide excellent relief of pain and anxiety with least adverse effects for the placement of ophthalmic blocks.

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