The sensitivity of the longitudinal and circular muscle layers of the rat's myometrium to oxytocin in vitro during pregnancy

1987 ◽  
Vol 65 (5) ◽  
pp. 773-777 ◽  
Author(s):  
D. J. Crankshaw
Keyword(s):  
Binding Site ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
The Other ◽  
Maximum Response ◽  
Primary Process ◽  
Maximal Force ◽  
Change In The Mean ◽  
The Mean

To test the hypothesis that binding site regulation is the primary process controlling the responsiveness of the rat's myometrium to oxytocin during pregnancy, I have studied the effects of oxytocin on longitudinal and circular strips of myometrium in vitro throughout pregnancy. Longitudinal muscle was as sensitive on day 10 of pregnancy (EC50 = 1.6 nM) as it was at term (EC50 = 1.3 nM) and there was no significant change in the mean maximal force developed in response to the hormone (2.1 ± 0.9 vs. 1.5 ± 0.3 N cm−2). Circular muscle on the other hand was essentially refractory to the hormone until day 21 of pregnancy at which time its sensitivity and the maximum response were similar to those of longitudinal muscle. These results indicated that regulation of oxytocin sensitivity in the two muscle layers was temporally different, and they suggested different mechanisms. The effect of oxytocin on longitudinal muscle was not compatible with the hypothesis that changes in binding site number regulate the responsiveness of the tissue, whereas the effect on circular muscle was.

Comparison of arteries with longitudinal and circular venous muscle from the rat

1977 ◽  
Vol 232 (2) ◽  
pp. H131-H139
Author(s):  
M. L. Cohen ◽  
K. S. Wiley
Keyword(s):  
Smooth Muscle ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Rhythmic Activity ◽  
Vasoactive Agent ◽  
Circular Smooth Muscle ◽  
Maximal Force ◽  
Portal Veins ◽  
Muscle Responses

Rat portal, mesenteric, renal, and femoral veins possess functionally responsive circular and longitudinal smooth muscle layers in vitro. In contrast to the dominant rhythmically active longitudinal muscle of portal veins, rat longitudinal mesenteric veins lacked rhythmic activity and developed maximal force equivalent to that of mesenteric circular muscle. Renal and femoral veins exhibited predominantly circular smooth muscle responses. Rat veins must be subjected to between 1 g (renal and femoral) and 4 g (circular portal and mesenteric) of passive forse for optimal responsiveness. Contractile response to vasoactive agent including carbamylcholine, serotonin, and norepinephrine was quantitatively different among veins. Femoral veins developed greater maximal force in response to norepinephrine than to KCL, and the responses to norepinephrine were not altered by cocaine. In contrast, cocaine markedly potentiated responses to norepinephrine in portal, mesenteric, and renal veins and, to a lesser extent, in the mesenteric artery. These data demonstrate heterogeneity in rat venous tissue and suggest that neuronal innervation may markedly influence responses to norepinephrine in some, but not all, rat blood vessels.

An in vitro Evaluation of Artificial Caries-like Lesions on Restored Overdenture Abutments

1988 ◽  
Vol 67 (3) ◽  
pp. 582-584 ◽  
Author(s):  
P.P. Kambhu ◽  
R.L. Ettinger ◽  
J.S. Wefel
Keyword(s):  
Light Microscopy ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
The Other ◽  
Type Ii ◽  
Restorative Materials ◽  
Abutment Teeth ◽  
The Mean ◽  
Materials Used

An acidified dialyzed gelatin gel system was used to determine the caries resistance of a variety of restorative materials used to obturate the canal orifice of overdenture abutment teeth. The restorative materials used were Tytin, Tytin + Copalite, P30 + Scotchbond, Fuji Ionomer-Type II, and Miracle Mix. Polarized light microscopy and microradiography were used to examine the caries-like lesions adjacent to the restorations. The lesions formed in the Fuji Ionomer-Type II and Miracle Mix groups appeared arrested at the wall adjacent to the restoration, and did not penetrate apically down the wall as did those associated with the other restorative materials. The mean depths of lesions adjacent to Fuji Ionomer-Type II and Miracle Mix restorations were significantly less than those of Tytin, Tytin + Copalite, or P30 + Scotchbond.

Flight muscle and flight activity of melon fly, Bactrocera cucurbitae (Diptera: Tephritidae)

2021 ◽  
Vol 30 (2) ◽  
pp. 179-185
Author(s):  
Farhana Ferdousi ◽  
Shanjida Sultana ◽  
Tangin Akter ◽  
Pinakshi Roy ◽  
Shefali Begum
Keyword(s):  
Longitudinal Muscle ◽  
Flight Muscle ◽  
Flight Activity ◽  
The Other ◽  
Bactrocera Cucurbitae ◽  
Male And Female ◽  
Melon Fly ◽  
Length Width ◽  
Flight Muscles ◽  
The Mean

The flight activity and flight muscle of the melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) were observed. The Tethered technique was used to observe the flight activity in this study. The flight activity, and wing and flight muscles were compared between male and female melon flies. The results indicate that the female was relatively better and strong flier than the male. The mean duration of the flight activity of the females was 13.90 min/hour and of the males was 7.12 min./hour. The mean length, width, volume of wings of the males were 6.07 mm, 2.67 mm and 10.99 mm³, respectively. On the other hand, the mean length, width and volume of the wings of females were 7.07 mm, 2.87 mm and 15.60 mm³, respectively. In case of wing muscles, the mean volume of dorsal longitudinal muscle (DLM) in male and female was found 5.20 mm³ and 5.67 mm³, respectively. The mean length of flight wing muscle of male and female was 2.22 and 2.23 mm, respectively and the mean breadth of male and female was 1.65 and 1.77 mm, respectively. Dhaka Univ. J. Biol. Sci. 30(2): 179-185, 2021 (July)

Age-related changes in colonic function in rats

1984 ◽  
Vol 247 (5) ◽  
pp. G542-G546 ◽  
Author(s):  
J. N. McDougal ◽  
M. S. Miller ◽  
T. F. Burks ◽  
D. L. Kreulen
Keyword(s):  
Electrical Stimulation ◽  
Age Groups ◽  
Circular Muscle ◽  
Colonic Transit ◽  
Maximum Response ◽  
Suitable Model ◽  
Fischer 344 ◽  
Age Related ◽  
Muscle Histology

Aging in humans is associated with changes in gastrointestinal function. We wanted to determine whether a similar phenomenon occurs in rats and whether rats would be a suitable model to study changes in the gastrointestinal tract with age. Intestinal transit, response in vitro of circular colon strips to bethanechol and electrical stimulation, and colonic smooth muscle histology were compared for post-pubertal (5-12 mo) and senescent (25-28 mo) male Fischer 344 rats. Colonic transit of 51Cr was decreased 45% in senescent rats in comparison with younger rats. The maximum response of circularly oriented muscle strips from senescent rats to electrical stimulation of nerves was 32% less than the maximum response of strips from postpubertal rats. Likewise, the maximum response of the muscle strips to bethanechol was 16% less in the senescent group compared with the postpubertal group. There was no difference between the two groups in the EC50 of bethanechol. The thickness of the muscle layers and the percent circular muscle of strips fixed at optimum length were the same in both age groups. The senescent rat appears to be a useful model for the study of gastrointestinal changes with aging.

STUDIES ON THE IN VITRO PRODUCTION OF CORTICOSTEROIDS BY ADRENAL GLANDS FROM NORMOTENSIVE INDIVIDUALS AND HYPERTENSIVE PATIENTS

1962 ◽  
Vol 40 (1) ◽  
pp. 285-301 ◽  
Author(s):  
Jean Davignon ◽  
Erich Koiw ◽  
Wojciech Nowaczynski ◽  
Gilles Tremblay ◽  
Jacques Genest
Keyword(s):  
Cushing’S Syndrome ◽  
Adrenal Glands ◽  
Cushing's Syndrome ◽  
The Other ◽  
Malignant Hypertension ◽  
Unit Weight ◽  
Chromatographic Technique ◽  
Acth Stimulation ◽  
The Mean

The production of aldosterone and other corticosteroids by adrenal glands surgically removed from 5 normotensive subjects with renal disease of various types, 11 patients with arterial hypertension, and 2 with Cushing's syndrome was investigated in vitro by the incubation chromatographic technique. The rate of steroid formation per unit weight of tissue was markedly lower in severe and malignant hypertension and slightly higher in benign hypertension as compared with the rate in normotensive controls. The amount of steroid released varied widely from one gland to the other and showed marked overlapping between the various groups; these variations were most prominent in benign hypertension, less in the normotensive group, and least evident in severe and malignant hypertension. The response of steroidogenesis to ACTH stimulation in vitro was slightly reduced in severe and malignant hypertension. The mean output of aldosterone by adrenal glands from hypertensives was slightly above the mean value obtained with normotensive control glands. The percentage of aldosterone formation in respect to total steroid production was roughly correlated with the severity of hypertension. In four hyperplastic adrenals obtained from two cases of Cushing's syndrome, the in vitro formation of steroids per unit weight of tissue and the response to ACTH did not differ significantly from that found in glands obtained from the other patients under study. The value of in vitro studies for the assessment of the functional capacity of the adrenal cortex is discussed.

scholarly journals Inhibition of Demineralization at Restoration Margins of Z100 and Tetric EvoCeram Bulk Fill in Dentin and Enamel

2019 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Cristina Leon-Pineda ◽  
Kevin Donly
Keyword(s):  
Light Microscopy ◽  
Polarized Light ◽  
In Vitro Study ◽  
The Other ◽  
Solution Ph ◽  
Class V ◽  
The Mean ◽  
Student’S T ◽  
Student’S T Test

Recurrent caries is still considered the main reason restorations need to be replaced. There are different materials available now that promise to reduce the possibility of recurrent caries by releasing fluoride and inhibiting restoration marginal caries. The purpose of this in vitro study was to evaluate the demineralization inhibition potential of a non-fluoride-releasing resin (Z100TM 3M, St. Paul, MN, USA) and a glass containing resin-based composite (Tetric EvoCeram Bulk Fill, Ivoclar/Vivadent AG, Schaan, Liechtenstein), which contains fluoride. Class V preparations were placed on 22 premolars; the gingival margin was below the cementoenamel junction and the occlusal margin was placed above the cemento-enamel junction. Ten teeth were randomly selected to be restored with Z100 while the other 10 were restored with Tetric EvoCeram Bulk Fill. Both groups were restored following manufacturer’s instructions. All teeth had an acid resistant varnish placed within one millimeter of the preparation margins. Both groups were placed in artificial caries challenge solution (pH 4.4). At the end of the 4 days; 100 µm buccolingual sections were obtained for each tooth; these were photographed under polarized light microscopy and the demineralized areas adjacent to the restorations were measured and quantified. The mean (±S.D.) area (µm2) of demineralization from the occlusal margin (enamel) and dentin margin were: Z100 2781.889 ± 1045.213; 3960.455 ± 705.964 and for Tetric EvoCeram Bulk Fill 1541.545 ± 1167.027; 3027.600 ± 512.078. Student’s t-test indicated that there was significantly less enamel and dentin demineralization adjacent to Tetric EvoCeram Bulk Fill compared to Z100; there was significantly less demineralization in enamel compared to dentin in both Tetric EvoCeral Bulk Fill and Z100. Tetric EvoCeram Bulk Fill performed better inhibiting demineralization at restoration margins when compared to Z100 and provided better demineralization inhibition in enamel than cementum/dentin.

Effect of Different Intermediary Bases on Microleakage of a Restorative Material in Class II Box Cavities of Primary Teeth

2017 ◽  
Vol 40 (2) ◽  
pp. 82-87 ◽  
Author(s):  
Faika Y. Abdelmegid ◽  
Fouad S. Salama ◽  
Waleed M. Al-Mutairi ◽  
Saud K. Al-Mutairi ◽  
Sultan O. Baghazal
Keyword(s):  
Primary Teeth ◽  
In Vitro Study ◽  
Class Ii ◽  
Positive Control ◽  
Negative Control ◽  
The Other ◽  
Control Groups ◽  
Significant Difference ◽  
The Mean

Introduction The aim of this in vitro study was to assess and compare the effect of different intermediary bases on microleakage between tooth and a nanocomposite interface in Class II box cavities in primary teeth. Methods Standard Class II box cavities were prepared in 52 primary molars and randomly divided into 9 groups according to the intermediary base used (Multicore Flow, Fuji II LC, SDR, Smart Dentin Replacement, and Biodentine). All specimens were subjected to thermocycling and prepared for microleakage testing and evaluation. Results There was significant difference in the mean ranks of microleakage between the 9 groups, which was observed in the gingival side (p<0.0001) and the occlusal side (p<0.0001). The mean ranks microleakage was significantly higher with experimental SDR, experimental Multicore Flow, and positive control materials when compared with the other 6 groups. The microleakage mean ranks were statistically significantly lower in experimental Fuji II LC, experimental Biodentine, and all negative control groups when compared with the other 3 groups. Conclusions Microleakage is affected by the application of intermediate material. Experimental Biodentine and Fuji II LC showed the lowest microleakage while experimental SDR and experimental Multicore Flow showed the highest microleakage.

Effects of autonomic drugs on cat colonic muscle

1981 ◽  
Vol 240 (5) ◽  
pp. G361-G364 ◽  
Author(s):  
S. Anuras ◽  
J. Christensen
Keyword(s):  
Muscarinic Receptors ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Adrenergic Drugs ◽  
Longitudinal Strip

The cat colon was divided in vitro into four equal segments, and one transverse and one longitudinal strip (1.5 cm x 2.5 mm) was taken from each. Transverse strips contracted rhythmically, each strip generating 0.9–1.2 g force. Longitudinal strips contracted irregularly, each strip generating 11.9–16.8 g force. Acetylcholine (10(-7) to 10(-5) M) and physostigmine (10(-8) to 10(-5) M) increased frequencies in longitudinal (P less than 0.05) but not in transverse strips (P greater than 0.05) and increased amplitudes in both (P less than 0.05). Atropine (10(-8) to 10(-6) M) reduced frequencies and amplitudes in longitudinal strips (P less than 0.05) but only amplitudes in transverse strips (P less than 0.05). Phenylephrine (10(-7) to 10(-5) M) and norepinephrine (10(-7) to 10(-5) M) increased amplitudes in transverse strips (P less than 0.05) but decreased frequencies and amplitudes in longitudinal strips (P less than 0.05). Isoproterenol (10(-7) to 10(-5) M) decreased frequencies an amplitudes in both transverse and longitudinal strips (P less than 0.05). Dopamine (10(-7) to 10(-5) M) decreased amplitudes in longitudinal strips (P less than 0.05). Tetrodotoxin (10(-7) M increased amplitudes in transverse (P less than 0.05) but not in longitudinal strips (P greater than 0.05). Both layers are affected by cholinergic and adrenergic drugs. Muscarinic receptors are excitatory in both. alpha-Adrenergic stimulations result in excitation in circular muscle and inhibition in longitudinal muscle. Circular muscle is dominated by an inhibitory neural tone.

Differential inflammatory modulation of canine ileal longitudinal and circular muscle cells

1999 ◽  
Vol 277 (2) ◽  
pp. G341-G350 ◽  
Author(s):  
Xuan-Zheng Shi ◽  
Sushil K. Sarna
Keyword(s):  
Receptor Antagonist ◽  
Muscarinic Receptor ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Muscle Contractions ◽  
Receptor Subtypes ◽  
Relative Role

The aim of this study was to identify the subtypes of muscarinic receptors that mediate in vivo and in vitro canine ileal longitudinal muscle contractions and whether their role is modulated by inflammation. Previous studies have reported that circular muscle contractions are suppressed in ileal inflammation induced by mucosal exposure to ethanol and acetic acid. We found that inflammation had no significant effect on in vivo and in vitro spontaneous or muscarinic receptor-mediated contractions of the longitudinal muscle. The longitudinal muscle contractions were mediated primarily by the M3 receptor subtype. However, the IC50 of the M2 receptor antagonist methoctramine was only 10 times greater than that of the M3 receptor antagonist 4-DAMP in the longitudinal muscle, whereas it was 224 times greater in the circular muscle. M2receptor-coupled decrease of intracellular cAMP occurred in the longitudinal but not in the circular muscle from the normal ileum. Inflammation did not alter this coupling in the longitudinal muscle but established it in the circular muscle. In conclusion, M2 receptors may play a greater role in the mediation of longitudinal muscle contractions than circular muscle contractions. Inflammation does not alter the contractility or the relative role of muscarinic receptor subtypes in longitudinal muscle cells. However, it modulates the M2 receptor coupling to adenylate cyclase in the circular muscle.

The Effect of Casein Phosphopeptide-Amorf Calcium Phosphate and Acidulated Phosphate Fluoride Gel on Dental Erosion in Primary Teeth: An in Vitro Study

2017 ◽  
Vol 41 (4) ◽  
pp. 275-279 ◽  
Author(s):  
Eda Arat Maden ◽  
Özge Acar ◽  
Ceyhan Altun ◽  
Günseli Güven Polat
Keyword(s):  
Surface Roughness ◽  
Protective Effect ◽  
Primary Teeth ◽  
Artificial Saliva ◽  
Soft Drink ◽  
Dental Erosion ◽  
The Other ◽  
The Mean ◽  
Casein Phosphopeptide

Objective: This study aimed to investigate the effect of acidulated phosphate fluoride (APF) gel and casein phosphopeptide/amorphous calciumphosphate (CPP-ACP) on the dental erosion produced by carbonated soft drink in primary teeth. Study Design: This study evaluated by an in vitro model the effect of APF gel and CPP-ACP on the dental enamel previously subjected to erosive challenge with carbonated soft drink. Sixty sound human primary molars were prepared by embedding the crown sections in acrylic resin blocks leaving the enamel surfaces exposed. The surface roughness of the enamel was measured with prophilometry at baseline. Specimens were randomly divided into three treatment groups (n:20): artificial saliva, CPP-ACP, 1.23% APF gel. All specimens were then exposed to an erosive challenge of carbonated soft drink and artificial saliva for 20 cycles of 20 seconds each. Demineralization-remineralization cycles was repeated twice at eight-hour intervals and roughness values were measured. Enamel samples were treated with artificial saliva, CPP-ACP, 1.23% APF gel applied for 10 min after erosive challenge. The arithmetic average roughness (Ra) readings were recorded after remineralization agents were applied. Results: The mean surface roughness in all groups increased significantly after erosion process and decreased after remineralization treatment. After treatment, the mean surface roughness of the 1.23% APF gel group was significantly less than the other groups and the mean surface roughness of the artificial saliva group was significantly more than the other groups. 1.23% APF gel showed the highest protective effect against erosive enamel loss. Conclusions: Under the conditions of this study, artificial saliva, CPP-ACP and 1.23% APF treatments were able to reduce erosive enamel loss produced by carbonated soft drink in primary teeth. However, 1.23% APF gel showed the highest protective effect against erosive enamel loss.

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